This post over at the Naked Ovary reminded me of a really dumb thing I did at Blockbuster while trying to rent movies one day. I was in a hurry and there was a long line, so by the time I got up to the register, I was already fairly irritated with the teenager manning the cash register. I slapped my movies down on the counter, with my Blockbuster card already pulled out and on top of them...
BlockBoy: [picks up movies and my card, and puts card back down on the counter] Ma'am, I'll need your card.
Me: [looking through my wallet for money, annoyed] I gave it to you.
BlockBoy: [looking embarrassed] Um, sorry ma'am, but I can't check these out without your card.
Me: What is your problem? It's right there! [still looking through wallet, gesturing to my card on counter]
BlockBoy: [stiffly] That's a library card.