"Okay, well, unless there's any other questions, I guess you guys can leave a little bit early today."
People start packing up their joints, etc. Obviously everybody's hella pumped that we got out a little bit early. But before you know it,
"Um, actually, I have a two-part question."
I'm going to start slapping people when they do this. The most frustrating part is that they seemingly don't even realize how selfish they're being. I confronted the offender afterwords and non-jokingly joked that he just wasted 5 minutes of everybody's time, and he looked at me with a quizzical stare.
This needs to be on par with other highly socially unacceptable things, like ratting out your friends or eating dinner before everybody has their food. Parents need to educate their kids on these kind of manners. Because I am sick and tired of people asking questions after the class has essentially ended.