Not being confident enough
Matt Raible: No, one of the misconceptions when you're speaking on a topic is that you need to know everything. You're afraid that the founder of the open-source project you're talking about is going to be in the audience and they're going to call you out if you're wrong. That never happens. It's rare that someone who knows the topic better than you will sit in your talk because they will go to other talks.
The best time to blog about something is when you're learning it because that's when you find all the different nuances that other developers are going to find. If you know the tech because you wrote it, or just know it well, then you're not going to know those little things that people stumble upon. I think the best conference speakers are people who just learned the topic a few months before, because they know all the pain that they went through.
Geertjan Wielenga: If you're standing in front of a big crowd and...