Please don't make me give you change for a 5 dollar bill, then tell me that you're sorry that you can't tip me. It's kind of rude.

I don't mind being stiffed (okay I do), but if you're going to do it, be a man about it and write the total on the credit card slip. I do rather enjoy telling people that they have fill out the slip completely and making them write all those zeros right in front of me though. Man up!