I'm not a big fan of collecting a lot of change and small bills. So, when I have a bill that is say $17.83 and I survey my available funds, I may end up handing the cashier $23.08. They're always seem a bit perplexed until they punch it in the register. In this case my change would be a nice tidy $5.25.
A friend went to a high school musical, paid for himself, his wife and two children. The girl couldn't figure out how much to charge them (different rates for the little kids) so he finally told her and she still had trouble making change from a 20. And this was about 10 years ago.