I hate when customers come to the register with a whole cartload of stuff they're still trying to decide on. Like changing your mind about a few items is understandable, but I have people come to the checkout line with like 8 Michael Kors purses and a bunch of other stuff that they clearly never intended to buy all of, which means we have to put the majority of it back.

Oh, and triple the annoyance if they do it five minutes before we close.