Why I Need an "Off" Switch for My Mouth

During a recent conversation the person I was talking with mentioned that they couldn't read.  This person is continually amazing me with  his extensive knowledge of (sometimes) random facts. In retrospect, I don't know what I thought he could have meant; but, at the time, I thought surely this intelligent person couldn't possibly mean that he was actually illiterate.

I said, in a whiny mock-sympathetic voice, "Oooh, I'm sooo sorry. You can't read? Reeally?"

Well, that is exactly what he meant.

Woops.

Ironically, we had just finished having a conversation about how I'm always putting my foot in my mouth, saying the most ridiculous things to people. This person claimed he had the same problem, so perhaps there is a chance he will forgive my stupidity.