Something I find incredibly rude — when a cashier starts checking out the next person in line, before the other person has gotten his items together and walked on. I understand cashiers are under a time crunch. They're expected to get people through quickly. But they're also expected to be polite. Nothing worse than trying to put your card back in your wallet and put groceries in your buggy and the cashier is already scanning the next person's items. And it's just as bad switched around. One cashier got mad at me the other day because I was waiting on the person in front to finish and move before I shoved them out of the way to scan my card.