I have discovered the ultimate embarrassment.
The ultimate embarrassment is having 30 people you're supposed to be teaching all sit and watch while you UTTERLY FAIL to get the hookup from your laptop to the projector to work. As an added bonus, you can get stuck improvising a 40-minute blackboard talk on how to do on-line research for primary sources instead of giving your carefully prepared on-line demo. I think the only way it could've been made more embarrassing would be if I'd forgotten to wear pants. Maybe I'll try that next week.