Here's one thing (among many) that really annoys me:
Sometimes when I go to purchase an item in a shop I like to give exact change. I don't want to keep the line waiting, but if I know it'll only be a few seconds, I give it a try. Or maybe I'm pulling out a credit card. I really don't take that long, honest! For some reason, though, cashiers are increasingly impatient creatures. I can't help but notice when the tapping begins. Their index finger, or sometimes a few of their fingers, tap, tap, tap on the counter until I procure my payment. I find this to be the most irritating habit, worse than anything my cat does while waiting to be fed. In fact, when the tapping begins, I have started a habit of my own. I slow it down. This explains why I don't drive. Can you imagine what would happen if people honked at me?