I have a pet hate, people who form one queue, when there obviously should be more, and then give you dirty looks when you ruin their 'hedge your bets' formation and create a second queue.
It isn't that I can't wait, it's just annoying when you have to extend the queue to the point that you're obstructing others from passing by. And when I've a heavy shopping basket in my hand, having folk squeeze past just gets ridiculous and sometimes rather painful?