What's the most mortifying thing you've ever said to someone before your brain caught up to your mouth?

I asked someone today if the Aggie's mascot was a longhorn. I think I killed her. Couldn't just ask what it actually was and let her talk about something she likes. Nope. Went straight for the pearl-clutcher before I could rein it in. And now I've let someone else at work take the last 3 calls when we're supposed to be taking turns but I don't think I should talk anymore today. It's not safe.

Edit: Because some of you are asking, the longhorn is the mascot for the Aggies' biggest football rival. Football in Texas is right up there with God, guns, and legislation controlling human rights.

Let me put it this way: the imagined transgression level is like I asked a Ukrainian if they were from Russia. Offended doesn't even begin to cover it.