What's really funny is that convenience store clerks will card you for purchasing beer. I'm 42 and the other day the clerk actually asked me for ID. It's flattering I suppose that I may look young, but I damn sure don't look like I'm under 21. But with a credit card, there are no rules - most clerks will swipe the card and hand it right back to you. Every once in awhile I'm in a mood and I'll say aren't you going to check my ID?