My worst experience led to a couple of hours in the police station.
See, I was watching Dark Knight for the third time (first time was with a girl who would not shut up, and the second time was ruined by a kid who would not stop yelling) when I noticed the guy sitting beside me had his camcorder out and was recording the movie.
Wanting to do my civic duty, I told him off and asked him to put it away. Guy pulls a knife on me and tells me to shut up or he'll gut me. So I sit there for the better part of a half hour with a knife sticking into my side.
During a lull in the movie's action, I tried to wrestle the knife away from the would-be pirate. It ended up in a brawl, and the guy got arrested. I, meanwhile, had to stay at the station to be interrogated by the cops.
But yeah. Apparently, the third time is NOT a charm.