I'm an idiot. I know. There's proof.
I'm flipping through a large stack of bills at lunch today and notice that one of my credit cards has a couple hundred in charges on it. "That's odd," I say to myself, since I haven't used the card lately, so I look at the detail. It shows a handful of small cash advances, together with your typically enormous bank fees for credit card cash.
It takes a minute before it hits me. I've been using my credit card (issued by the same bank) as my ATM card. Dammit. I pull out my wallet, and sure enough, I have the blue credit card, which happens to look almost identical to the blue ATM card, parked right there in the second slot. When I restocked the wallet after Vegas, I must have put in the wrong card. How dumb is that?
Tying my general idiocy into an ongoing theme here:
Now, I am one hundred percent positive that when you navigate the 37 levels of prompt screens at my bank's ATMs to make a simple withdrawal, you have to tell it where you want the money to come from. I know for a fact that I selected "Checking" each and every time. And yet, instead of a helpful "You're using a card that's not linked to your checking account you fricking idiot" screen, the machine just gave the the money anyway and charged the credit card.
Today's real lesson: The damned ATMs are rigged too.