Being late to a theatre/ ballet/ opera and disturbing everyone during the performance so you can find your seat?
I'd also count the cinema and a myriad of other events. Don't you make sure that you're on time, and if by some chance you can't avoid being late, wouldn't you stand at the back until an interval? People who stay in the bar until start, and then disrupt everyone, climbing over them to their seats, clutching half drunk drinks drive me nuts. So AIBU?