If you've ever attending a presentation on a software development technical topic, the law of Developers in the Audience always states that these 2 events will happen: 

1.  When the presenter makes a mistake (even a little one), there will be a jeer, snicker, giggle, or some sort of snarky behavior by someone in the audience.  It someone will be ready to pounce at a glitch or mistake and expose the presenter as a fraud.

2.  Someone will always ask for the font size to be bumped up, but the person requesting this is never sitting in the front.