What's the rudest customer you've ever come into contact with.?

There was a woman who came through my line (I'm a cashier at a grocery store) and she started bitching at me about how long the lines were. Then, half the stuff she bought didn't have a barcode, so I had to call different departments to find out the prices (most people who buy that stuff write down the price like the sign says) and she just got even meaner. THEN she went to swipe her fod stamp card, and SHE couldn't remember her pin, so she starts cussing at me. I don't handle that well. I started tearing up, because I get really emotional when people yell at me, and my day had already been total ****. The boy working the next register over saw I was gonna cry and came over and started bithcing the lady out :) He told her that if she was going to be disrespectful to employees trying to help her, then she could leave. She told him to f**k off, and went up to our shift manager to complain- and he told her to leave or he would call security up. Haven't seen her since. :]