First Slide Conference Presentation Judo (Notes)

Conference Presentation Judo (notes)

A substantial amount of the sense of this talk is not in the slides. This document will try to relate some of the things I said during the talk itself that might not otherwise be apparent. It may also elaborate, amplify, and explain where necessary.

The notes will also explain the jokes, so if you read the notes without reading the slides first, you'll be getting explanations of jokes you haven't heard, and none of it will be funny. So read the slides before the notes, or concurrently with the notes.

As in the talk itself, everything in these notes is intended seriously, even when it appears to be facetious.

**NEW** An audio recording of this talk is available courtesy of Dave Wheeler and

Slide 1: Conference Presentation Judo

Earlier that morning I had given a talk on Mailing List Judo, which was a tongue-in-cheek guide to the best way to navigate the social obstacles of the perl5-porters mailing list and to get your patches to Perl incorporated into the main source. The 'judo' of the title referred to the idea that one could use the negative features of the mailing list against themselves.

That class finished with a slide that said "Come back next year for my talk on Conference Presentation Judo" over a picture of a happy baby. (See below for more details about the baby.) I was serious about the Conference Presentation Judo talk, and in the days before the conference I made several pages of notes for it.

Just before I left for the conference, Kevin Lenzo wrote to tell me there had been a cancellation and to ask if I could fill an extra slot. I gave Kevin a choice of five talks, and he chose this one.

The picture on this slide is an extreme closeup of my face. Observant viewers sometimes remark that it's unusual that my pupil is so dilated even though it appears that I'm looking directly into a light. When this picture was taken I had just returned from the ophthalmologist, who had forcibly dilated my pupil so he could look in.

Slide 2: Conference Presentations

The talk was aimed primarily at people who will be giving a three-hour tutorial at a conference like TPC or Usenix.

Many people have told me that they think it will be helpful to them in preparing talks of other lengths for other venues. But if your talk is not a three-hour conference tutorial presentation, you should carefully think over all the advice I give, because some of it may not be appropriate for talks of other lengths to other audiences.

Several former TPC tutorial speakers were in the room. Also present was Robert Spier, who was scheduled to give his first TPC tutorial the following month. I had originally been scheduled to speak at the same time as Robert, but I had my talk moved so that Robert could attend.

I really do believe that most tutorial speakers are terrible. One of the perks of doing a tutorial is that you get to attend the other tutorials for free. I rarely last through more than half an hour of anyone else's tutorial. Partly this is just a short attention span, and partly it's that I pick things up much quicker than the typical student. But a lot of it is that the tutorials are very poorly organized and presented.

Readers should note that this talk is about tricks that might not be obvious and advice you haven't heard before---I'm not going to explain the fundamentals of public speaking, such as "always face the audience." This talk assumes you've heard that already. If not, please visit Peter Urs Bender's Secrets of Power Presentations. I didn't find this until long after I wrote the talk you're now reading, but I agree with almost all of his advice.

Slide 3: Conference Presentations

When I gave the talk at the conference, I omitted the picture of Damian, because I decided that it didn't make any important point except to reveal one of the more unpleasant sides of my personality. But both Damian and my wife agreed that it was funny, so I put it back for the web version.

Slide 4: The Biggest Mistake You Can Make

On the previous slide, I considered mentioning that one of the ways in which some people fail to have aptitude for tutorial presentation is to have a small bladder. I was blessed with an enormous bladder, which is a valuable asset. I was going to put a picture of a bladder on the slide. I decided against the whole thing because I didn't want to telegraph the joke that appears on this slide.

After the talk, Damian and I were discussing these slides, and Damian congratulated me on the clever visual pun in the illustration.

I said, "What pun?"

"Well, of course, she's just bowing."

"No, she isn't."

"What's she doing, then?"

"She's doing exactly what the slide is about."


I agree, it would have been very clever to think of using a picture of someone who was merely bowing. It never occurred to me. And there you have the difference between me and Damian. Damian is clever; I am direct.

Slide 5: The Second Biggest Mistake You Can Make

As far as I know, I have never done this.

Slide 6: The Biggest Mistake You Can Make

I have nothing in particular to say about this slide, so I'll address a couple of issues I forgot to mention in the talk. In a talk of longer than about twenty minutes, you should really have some water handy. You can get into big trouble if your mouth dries out in the middle. Obviously, it can become difficult to continue talking. Even worse, some people have the problem that if they try to talk with an insufficiently lubricated mouth, their spit tends to fly around a lot. Ick.

The converse of this, however, is that you should be careful not to drink too much unless you're one of those lucky people like me who doesn't have to care. I usually go through about a quart and a half of water in a 90-minute talk, but not everyone can do this. Ration your water supply unless you're sure you can handle it all. Don't try this at home folks; I'm an experienced professional.

Do not try to drink coffee while you're talking. This is for several reasons. First and most obviously, the caffeine is a diuretic. But more important, coffee, at least when it contains milk, is a lot more viscous than water is, and if you try to drink coffee and talk at the same time, you are likely to inhale the coffee. Stick to water.

Similarly, it's probably a good idea to avoid eating while talking. The problems here are manifold and obvious: You might choke. You might spray food particles around. You might become impossible to understand. You might inadvertently let the audience see the food after you've chewed it but before you've swallowed it. (Ick.) Like all the advice in this talk, this must be adjusted for each person. Even with all these potential problems, I eat during my morning talks anyway. Why? Because if I don't eat, I get cranky and irritable around 11 AM, and then I start to tell audience members how stupid they are, and that's worse than letting them view my semi-chewed breakfast. You have to work with what you have.

Slide 7: The Single Biggest Mistake You Can Make

The advice on this slide is crucial, and not at all obvious without the explanation, which I delivered orally.

The reason you must not discharge the class early or late for break is this: If you let them out them early, the hotel staff will not yet have finished setting up the coffee and cake service. If you discharge them late, the other classes will already have eaten up the best cakes. The cakes are the high point of the tutorial for many people, and if you screw up the cake schedule, you will be savaged on the evaluations. People love cake.

The picture illustrates this, showing me in the act of enjoying a Sacher Torte. My in-laws sent this to us from the Hotel Sacher in Vienna.

Slide 8: On Content

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Slide 9: On Content

This is one of those slides where I was afraid that people would think I was being facetious. I wasn't. Gilbert Highet says much the same thing in The Art of Teaching. A talk with good presentation and poor content beats one with good content and poor presentation. This is because the first talk will at least pass the time amusingly; the second will be a deadly bore and you won't learn anything anyway.

Of course, the trick is to have good presentation and good content.

Slide 10: On Content

By the way, I recommend The Art of Teaching very highly. And here's an interesting phenomenon: If you look at the Amazon customer reviews of it, you find that everyone agrees that it's great except for M.Ed. students in Missouri and southwestern Illinois.

Slide 11: On Content

Slide 12: On Content

Apparently when I got to the "Introduction to XML" slides, a gentleman in the audience turned pale. He got out his laptop, brought up the slides for his own "Introduction to XML" class, and they matched my fake slides almost exactly.

Despite this, I swear that the assertion on slide 14 is true: I was not thinking of any specific instructor or class. I just chose XML as an unusually boring and buzzword-ridden example.

The truth is, the problem of long pointless introductions in tutorials is almost universal. Nearly everyone does it.

At YAPC::Paris in 2003, someone mentioned to me that when he is at a conference, he never hurries back from lunch; he said that if you miss the first thirty minutes of a tutorial, you often arrive just as the instructor is getting to the interesting part.

This was exactly the reason that I started the Lightning Talks sessions. I decided that if the speakers couldn't get to the point promptly, then dammit, I was going to force them to get there or else get off the stage. It has worked pretty well. Every year has a couple of people who can't seem to say anything, but I get rid of them quickly.

Blaise Pascal once wrote "I am sorry that this letter was so long, but I did not have time to make it shorter." To prepare good talks or articles, authors must ask themselves "What am I really trying to say here? Why is it important?" The severe constraint of a five-minute time limit forces a distillation of thought and a clarity of exposition not usually found in longer talks.

Some day I'll write an essay on the theme "Constraint is liberating."

Some time ago Nat Torkington pointed to a discussion of conference design which criticized 45-minute sessions as too short. This article said, in part:

Last fall at the O'Reilly P2P & Web Services Conference I noticed that the short sessions (45 minutes) prevented every relevant point from being addressed and discussed.

The author of the article apprently considers this a disadvantage. I consider it a benefit. So did Voltaire. He said "The secret to being a bore is to tell everything."

The author of Nat's article continued:

Panels and sessions served as instigators of discussions that continued in the hall afterwards, or over lunch in the courtyard.

Again the author seems to think that this is a bad thing. I strongly disagree. Having conference attendees come up to a microphone to ask questions discourages dialogue. It encourages a hierarchy of authority; it discourages networking; it encourages thoughtlessness. Having conference attendees meet the speakers in the hallway or over lunch does the opposite: it encourages dialogue, networking, and thoughtfulness, and neutralizes the hierarchy. The participants can have a meaningful exchange of complex ideas, conversing as equals, instead of being forced into the roles of supplicant and hierophant.

And, of course, having long conference sessions encourages a lot of blather.

Nat asked folks for feedback on this, and I said:

I'm sure my opinion won't be a surprise, but I think that even 45-minute sessions are too long for most speakers. If you give them any more time, they just waste it. If they want to talk for twice as long, let them cut the talk in half and send two proposals.

TPC used to have groups of three related 20-minute talks scheduled into a one-hour slot. I liked those. If I were scheduling a conference, my motto would be "twenty is plenty."

Slide 15: The Long Introduction

Nobody is born knowing that the Long Introduction is a mistake, including me. My first conference tutorial had an enormous introduction. The topic was web application security. It began with a six-slide introduction section:

  1. Who Am I?
  2. What is this Talk About?
  3. Outline
  4. What is this Talk About?: Essential Questions of Security
  5. What is this talk not about?
  6. Kinds of Attacks

OK, so the introduction is finally over, right? No. The next sixteen slides were an "Overview of HTTP".

Finally, on slide 24, I got to the point.

If I were doing this over, I'd cut the introduction to two slides. One slide to provide the overview ("What is this talk not about" would turn into a single bullet point) and one slide to introduce me. Usually, nobody really gives a shit about the "Who Am I" slide, and I advise most speakers to throw it away; I've eliminated this wankery from almost all of my talks of the past few years. But in this case I'd leave it in, because I think it's important to establish credentials before talking about security.

Then I'd chop out the entire "Overview of HTTP" section. There is material later on that depends on it, so I'd insert the bare minimum necessary at the points where it was needed, either as one- or two-page digressions, or as off-the-cuff handwaving explanations. For example, later on in the talk there is a discussion of the mechanics of the HTTP 'basic authentication' protocol. At that point I'd probably mention in passing that the way HTTP works is that the browser sends a request message to the server and receives a response message in return. A couple of slides later I explained that the basic authentication protocol requires that the user's password be sent with every request; at that point I could interject a remark about how each request is logically separate, and typically the browser or the server (or both) tears down the TCP connection after the response is delivered. Each of these interjections would turn into a single bullet point and would replace a slide or two of blather. The detailed discussion of the format of requests and responses would probably turn into something like this: "These messages have headers, just like mail messages."

Here, as an example of what not to do, is the Long Introduction from my first tutorial. Don't read these if you're at work and you need to stay awake.

Slide 16: The Long Introduction

This slide raises a question that's puzzled me for a long time: Why do people attend these three-hour lectures anyway? I talked with Conway about this once, and he had some useful things to say, and pointed out that for many people, the lecture really is a good way to learn a few things. Still, I think these classes are far from optimal. You know, if you can get six people together who want one of these classes, you can pay me to come to where you are and give the class just for you, and you'll get a lot more out of it than if you paid to sit in a giant room with two hundred other people and hear a lecture. If you get seven people, they'll get a better class and save money. If you get twelve people, they'll save a lot of money. I don't know why more people don't do this.

I'm afraid some people interpreted my remark about 45-minute attention spans to be vaguely insulting to conference attendees. But it was certainly not intended that way. Really nobody can pay attention for more than about 45 minutes. Certainly I can't, and I have unusual powers of concentration.

I guess that the standard deviation of attention span is about 15 minutes, so that about 2/3 of the audience gets distracted by the end of the first hour.

Slide 17: A Bit of Advice

At this point I asked for a show of hands to learn how many people had heard this advice. Most of them had.

It's amazing that this awful advice has such a hold on people. If you contrast the traditional advice with my advice, it seems to me that mine sounds a lot more commonsensical. You're giving a technical talk; the attendees have gone to a lot of trouble and expense to be there. What could be more natural than "Get to the point"?

The third piece of advice ("Don't repeat; embellish") requires a little elaboration. You want to present each important idea more than once, because a lot of the audience won't really get it after the first example. So you show a second, different example, which has an interesting variation. The people who didn't fully grasp the concept the first time around now have an opportunity to see it again. The people who did get it the first time around will remain alert and interested because of the variation.

Here's an example. I want to convert a recursive function to an iterator. One example is a directory tree walker. A later example is a genomic sequence generator. (Given a pattern like <CGA>TT<CG>TT, produce strings like CTTCTT, GTTCTT, ATTCTT, CTTGTT, ...) Structurally, these are quite similar. But the tree walker involves some system programming details, while the sequence generator involves some parsing details. breadth-first and depth-first search both yield sensible results for directory trees, but only depth-first search makes sense for the sequences. With the sequences, a random search order can be interesting, so I introduce that as a variation. People who didn't understand the details of the tree walker get to see them over again, and people who did understand it get to compare the two examples and ponder the differences.

The photograph on this slide was taken by Meng Wong on his vacation in Australia.

Slide 18: Get to the Point

Notice that this one slide is the "introduction section".

The list of examples is rather devious. "Generating DNA sequences" is there because everyone knows that Perl was important for the Human Genome Project and the bioinformatics is a major research area, funded by the government and so on. If iterators are useful in bioinformatics, they therefore have some importance in the real world.

"Database searches" is there to convince the people who weren't convinced by bioinformatics. It's completely generic and completely universal. Every single person in the room has to perform database searches. It's also there because it's boring. Some people refuse to believe that anything interesting has any real value, so I always try to include an example from cost accounting if I can. Databases aren't as dull as cost accounting, but they're dull enough.

"Permutations" is there to hook the math-heads and academics. It's also there to impress people who don't know what permutations are but who are impressed by big words.

Slide 19: Get to the Point

The thing to notice here is how quickly I dive into the technical details. Slide 1 is the introduction section. Slide 2 introduces a specific problem we're going to solve. Slide 3 shows complete code; slides 4-5 explain how it works. Slide 6 presents the problems with the approach. Slides 7-9 show that these same problems appear in the context of permutation generation (the 'solution' in the Perl Cookbook has the same severe defects) and database search. Having established that these are common problems, I then show the solution: Slide 10-12 introduces the solution in the context of databases, because Perl's DBI module provides a ready-made example. Slide 12 ends by calling the solution structure an iterator; slide 13 backs up and answers the question "What is an iterator?" Now that the class has seen several examples of the problem we're solving, and one well-known example that uses iterators as a solution, they're ready to appreciate why they might care about the answer to the question "What is an iterator?".

Even if someone falls asleep after 45 minutes, they will know what iterators are for and have several examples of places where they are used and places where it would be a good idea to use them. They have an analogy with filehandles, which are a special case, and Perl's 'each' and 'readdir' operators, ditto. They don't know any techniques for implementing iterators, because I showed those after they fell asleep, but the code is still in the book and they can read it later. Mission accomplished.

Slide 20: Pictures

I think this may be the single best slide I've ever made.

Slide 21: Illustrations

Pictures don't have to be irrelevant or colorful. Even a monochrome box-and-arrow diagram breaks up the monotony of slide after slide of unrelenting text.

The atrocious pun here is that this was the illustration from the first page of a tutorial section on "autoloading".

Slide 22: Illustrations

This year I redid all my diagrams. I felt like a complete dumbass for having taken so long to figure this out.

Slide 23: Illustrations

Meng tells me that magazine designers follow the same rule. If they have a picture of a person, they will flip it over if necessary to get the person to be looking at the gutter instead of at the margin. I boastfully note that I figured this out for myself.

I wish I had used a better example person on this slide; I don't know why I went with Amelia Earhart. These notes show a better example. I use this picture of Randal Schwartz every chance I get because Randal appears to be so interested in the text.

Slide 24: Illustrations

Here we see a piece of useful advice: Everyone loves a happy baby. It's shameful to use such a dirty trick, but I didn't let my shame prevent me from using it three times at that conference. Hey, it's a dog-eat-dog world out there and if I can make more money by exploiting innocent babies, I will.

I found this picture by doing a Google image search for "happy baby". I got thirty thumbnails of the thirty happiest babies you've ever seen.

After I gave this talk, there was a rash of happy baby pictures in conference talks for the rest of the year. This showed that people didn't really understand what I was saying. I was not suggesting that people slather their talks in happy babies. My suggestion was that people should reinforce their points by appealing to base psychology. People are wired to love happy babies. People are wired to think that fruit is beautiful. People are wired to feel fear and horror at the sight of injuries and deformities. People are wired to feel disgust at the sight of shit and vomit.

Look at the picture of the DNA that I slapped on Iterators and Generators slide #2:

Google has 137,000 pictures of DNA molecules. Why did I choose this one? Because of the pretty colors, obviously!

If you are making the point that C++ is nasty, and you want people to be disgusted by it, one of the most effective things you can do is to put some turds on the page. People will feel real disgust, not in the front part of their brains, but way at the back, in the microcode. (I don't need to list all the ways this plan could backfire, do I?)

Slide 25: Speed

Everyone in the class wishes you would go at a different speed. Some people want you to go faster, some slower. On this slide, "median rate" means a rate which is faster than half the audience would most prefer and slower than the other half would most prefer. While this is the speed that's closest to everyone's preference, it's not optimal.

By '75-80% mark' I mean that I try to run my classes at a speed that is faster than 75-80% of the people in the class would most prefer.

Since hardly anyone will retain everything in your talk, you want to construct the talk in sections that are as independent as possible. The way to do that is to structure the talk like a tree. Graphs with cycles have more dependencies. You should cover the root nodes first because everything else depends on them and at the beginning of the talk everyone is still awake for it.

Slide 26: Speed

At a 75-80% speed, people will miss stuff; it will go by too fast for them to understand. But that was going to happen anyway.

The thing about synchronization points is very important. It's all very well to imagine your talk as the development of a single brilliant argument from start to finish, but if you do it that way, almost nobody will follow the whole thing. It's better to break the talk into sections that can be swallowed one at a time. Then if someone sleeps through section 7 and wakes up for section 8, they still get some value out of section 8, and they can use their knowledge of section 8 later on when they go back and try to reread the notes for section 7.

I guess the short version of all this is: If you have sections, you can go faster. The slower people will learn more because they can get some of the sections on the first pass and fill in the missing sections later; the faster people will learn more because you went faster.

Slide 27: The Guy in the Second Row

My original plan for this talk was to have "Seven Conference Attendees to Watch Out For", but the only one I could think of was the Guy in the Second Row. There could be two hundred people in the room with you, but for the Guy in the Second Row, they don't exist; he's there to have a dialogue with the speaker.

The Guy in the Second Row is not always a guy; I had a female Guy in the Second Row once. However, he does always sit in the second row. I do not know why.

My life has been full of Guys in the Second Row, but I had a very specific person in mind when I wrote this slide. Originally, there was a picture of him on the slide. Then I decided it was unfair, and added a note about how the person on slide 28 was actually much worse. Then I took the original person off of slide 27 and just went with the slide 28 person.

Slide 28: The Guy in the Second Row

This is a picture of me. This would probably have been more obvious if you had been at the talk.

Once I recognized the phenomenon of guy-in-the-second-row-ism, it didn't take me long to figure out that I was one of them. This is probably why I find Second-Row-ism so darn annoying. The faults we dislike most in others are those that remind us most of our own faults.

For a typical example, listen to Adam Turoff's talk on open source presentation systems.

Slide 29: Questions

I got this idea from Phil Agre. Unfortunately I can't find his original remarks. But almost everything Phil writes is worth reading, so have a look around his site. In particular, Networking on the Network contains useful advice for how to get the most out of a conference.

Slide 30: Accordion Sections

If you run out of time on slide 111 of 120, the evaluations will complain that you didn't finish the talk. But if you run out of time on slide 120 after having skipped slides 103, 105, 107, 109, 111, 113, 115, 117, and 119, nobody will complain at all. Go figure.

So, for example, my Tricks of the Wizards class ends with:

Topic# slides
Returning a False Value2
The Self-Replacing Stub2
Schwartzian Transform4
Build your own 'map'
(additional example)
Debug printing of strings1
Debug printing of lists1
Matching many patterns at once3
Selecting n different things1
Quick return with warning1

Sometimes people claim that a well-constructed class will fit the available time exactly, and if it's doesn't it is a defect in the design of the class. This is nonsense. No matter how carefully you construct the class, sometimes it will be too long and sometimes too short, because audiences are not all the same. Some audiences ask lots of questions; some ask very few. The same material that takes 150 minutes to cover in Hong Kong might take 220 minutes in Haifa. If you're going to finish on time in Haifa, the only good choice is to skip some material. The alternatives are to talkreallyfastforhalfanhour or else to tell people that there isn't time for questions. Both of these are inferior to cutting material.

Slide 31: The Bonus Section

Conference attendees like to see a big fat book. It makes them feel like they got their money's worth, even if most of the book is crap. After the conference is over and they've forgotten the tutorial, they still have the book, which proves to them (and their boss) that they were exposed to education.

One implication of this is that people will be happier if you print on only one side of each page; this makes the book twice as thick. It also gives the attendees a convenient place to make notes. (On the other hand, if your slides don't have space for notes already, you probably have too much text on the slides.) Unfortunately, one-sided printing wastes trees.

An easy way to bulk out the book is to attach a bunch of technical specs such as RFCs. Many speakers do this. However, the Bonus Section approach is more valuable and interesting. Even a small Bonus Section is worth having.

Calling it a "bonus section" instead of "random crap that I almost threw away" makes it sound like a benefit (which it is) instead of a liability.

Nearly everyone seems to have the problem of having too much material rather than too little. After you spend a lot of work writing up your slides, you don't like to cut them out and throw them away. You want people to see the results of your hard work. The result is that the class is too long and bloated. Having a bonus section makes it psychologically easier to chop stuff out of the class. You don't have to consign it to the trash can; it will go in the Bonus Section.

Slide 32: The Bonus Section

Slide 33: Digressions

People attending my Stolen Secrets of the Wizards of the Ivory Tower class at YAPC this year will note that I didn't follow my own advice here. I digressed extensively in the middle of a discussion of memoization to discuss ISO paper formats. A brief digression would have been acceptable. It probably would have been better to stick to the subject.

It's a good idea to have a few digressions. People will be happy if they come away from your class with one or two useful techniques or ideas. Some people will come away from the class thinking that the whole topic was a monstrous waste of time. But if you have a few well-planned digressions, you can salvage some of those people---maybe they thought that the Iterators were useless, but the class was worth while, because they learned about the scalar flip-flop operator.

Also, digressions are fun and interesting and spontaneous and wake people up.

Slide 34: Evaluations

The evaluations really are worthless. They seem to be designed to be worthless. They're filled out in a big hurry, in the two minutes between the end of the class and lunch time. They're anonymous. Most of the questions are checkboxes: "Too fast"; "Too slow". Suppose 45% of the submitted forms say "too fast" and 35% say "too slow". What conclusion should you draw from this? Evaluation forms ask questions like "Was there anything particularly positive or negative about the instructors" and then provide enough space for about twenty words. All of this strongly discourages thoughtful and constructive criticism.

The evaluations may be worthless, but that's what the conference staff uses to decide whom to invite back next year, so you need to get good ones. That's why this talk is all about making sure your class gets the best cakes.

Remember, unless at least sixty percent of the class says you're going too fast, then you're going too slow.

You really will get every possible complaint, no matter how pinheaded or absurd. Last year at Usenix I got an evaluation that had nothing on it except the complaint "Too cocky". I also got one that said "Thinks he's funny, but isn't." My favorite evaluation comment was from the person who came to Tricks of the Wizards and complained that the material was too advanced.

Slide 35: Evaluations

Good advice for this life in general. You can't count on getting approval or encouragement from other people, so concentrate on getting approval from yourself.

I sometimes imagine myself standing in judgement before God. God asks me, "Did you do the best job you could?" I want to be able to say that I did. If I can imagine telling God that I did good work, then that's good enough for me. If God is happy with my talk, then the conference attendees should be satisfied too.

Slide 36: Jokes

If you do begin with a joke, it must be a relevant joke. You can't win the audience by starting off with "A priest and a rabbi were fishing..."

This talk started with a couple of jokes. They were very successful. Bathroom humor may be juvenile, but it's universal. People are less offended by it than I thought they might be. The same caveat applies here, though: If you aren't a bathroom humor sort of person, then stay away from bathroom humor. I think one reason I can get away with it is that there's no coyness on my nature.

The advice on this slide has a more general version: Don't take any advice that is contrary to your nature, including the advice in this talk. If you're not a cynical, manipulative bastard, or if you hate babies, you might want to avoid pictures of happy babies. If pictures aren't working for you, maybe you shouldn't have them. There's probably even someone out there who can't give the best possible talk unless they sabotage the cake schedule.

This reminds me of a very clever suggestion that Meng made a few weeks ago. In one of my talks, I have a picture of two-headed sperm:

I was initially worried that some people might be offended by this picture. Meng's suggestion was that if anyone was offended, to tell them that it was a picture of gorilla sperm, which would make it all right.

This is very funny, but only because it's true.

Slide 37: Friendly Faces

I like to get Kurt Starsinic primarily because he's friendly looking. Kurt has an unusually honest, open-looking face. He also smiles a lot.

Incidentally, if you do have trouble with stage fright, here's a trick that worked well for me for a long time. I found that playing the harmonica in the bathroom before the talk was very helpful. Partly this is because it's distracting, and partly because it forces deep, rhythmic breathing. I don't expect you to run out and learn to play the harmonica, but the advice about distractions and deep breathing applies to everyone.

Slide 38: Friendly Faces

This is Placido the octopus. My wife and I have several octopuses at home, but Placido is the one who accompanies me to all my talks. Some people would probably prefer to bring prefer a teddy or a doggie.

Placido was named after Placido Polanco, a utility infielder for the St. Louis Cardinals. After YAPC was over, Placido and I went to the Cardinals game and were delighted to discover Polanco playing third base. (I had completely forgotten that Polanco played for St. Louis.) He was two for four with a double, scoring one run and driving in two. The Cardinals beat the Reds 3-2.

Slide 39: Small Change

It's a good idea in general to keep your hands out of your pockets while you're speaking. If nothing else, it projects nervousness. If your pockets are full of change, you'll jingle it, which will annoy the people who can hear; to the people who can't hear it will appear that you are fondling your genitals. If there isn't any change in your pocket, you may fondle unconsciously. All of this is very bad.

Slide 40: Insults

I'm not sure that this is actually good advice. It might be better to live your life without ever speaking ill of anyone. Sorry, I'm not yet a perfect sage.

In any case, if you're a seething cauldron of bile like me, and you just can't restrain yourself from insulting someone, then telling your audience that they're smarter than last week's audience seems like a reasonably safe escape route.

Slide 41: Proofreading

This is the thing about audiences that drives me the most bananas. Why do they have to be so uppity about little typos? But they are, and I've had to learn to live with it. When God asks me if I did my work as well as I could, I don't want to have to admit that my slides were full of typos.

If I were going to write an essay about how to give a good talk, the practice session would be the most important thing on the list after going to the bathroom beforehand. The practice session gives you a chance to find out what's unclear. The practice session gives you a chance to find out whether your first draft is fifty percent too long or only twenty percent. If you find yourself waving your arms a lot at certain points in the practice session, that tells you that you should add diagrams to the slides at those points. In the middle of the practice session, you can stop and take notes about how to improve the slides. You can do that in a practice session; it's harder to get away with it when the audience is paying four dollars a second to attend.

Practice sessions are less formal, so you won't be as scared and the audience will be more forgiving.

You can make some money by charging people five or ten bucks to come to the practice session; the attendees will be glad of the chance to get a $300 tutorial for $10. This also gets you valuable exposure, and people will leave feeling that you did them a big favor, especially if you spend some of the admission fees on making a handout to give them. Everyone comes out happy.

If you can't get a practice session together, or even if you can, you should give a private practice session with no audience. Give the whole talk, out loud, with nobody around, or perhaps give the talk to your dog. When you do this, you will discover that some things you planned to say come out sounding confused, some come out sounding unconvincing, some come out with unintentional, silly-sounding rhymes, some come out with bad rhythm, some are just too long. You can try saying things in several ways until you find the phrases and the pacing that you like.

Incidentally, this slide demonstrates that even the simplest illustration is better than no illustration at all. I think the giant comma is hilarious.

Slide 42: Biggest Mistake I Ever Made

Good conference presentation wear is slacks and a button shirt with a collar. You should look tidy and comfortable. But if a collar shirt will make you uncomfortable, you must wear something else, because nobody likes to sit for three hours and watch a speaker who looks like he is being garrotted. I always roll up the sleeves of my shirt, which may be untidy, but otherwise the sleeves bother me. Also, I like the way it looks, and for me, it's important to feel that I'm physically attractive when I give a talk.

Wearing suits does not make me uncomfortable---sometimes I wear mine just for fun---but it sure does make conference attendees uncomfortable. I was slammed on the evaluations for the suit. People were quite offended that I would dare appear before them in a suit. Geeks are very anti-suit. I don't think this is a good thing; I think it reflects an underlying insecurity and lack of self-knowledge. A suit is just clothes; putting one on doesn't change you into a different person. But most geeks don't seem to be comfortable enough with their own identities to feel safe dressing differently than usual.

Back before I was completely comfortable with the idea of wearing a suit, I explained it to myself by saying that I was in disguise, sneaking around deviously undercover, and that made me feel better. After a little while I got used to it. I think it's a bad sign that so many geeks are so frightened by the very thought of a suit.

Slide 43: Thank You

Always say 'thank you' at the end. That's just ordinary manners.

Thank you. I hope you found this helpful. Now get out there and get rid of that Long Introduction!

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