You know what bothers me? Professionally?
Going to some form of presentation in which the speaker has Xminutes to get their point across, but said speaker fails miserably. In other words, they go well over the time allotted.
This happened last night. Three speakers, one hour: GO. The first speaker went 25minutes. Fine, I can deal with that. The third speaker went 15minutes. Perfect. But that second speaker? Close to 45minutes.
You're an educator! You present information for a living! You must know how much you can fit into a given amount of time!
On top of that, the material presented wasn't even relevant.