What are your "foot-in-mouth" moments?

One time a co-worker was going on a trip (submarine deployment) .. he was a balding man.. knowing such deployments are stressful.. as I said “see ya later”.. I added “come back with some hair”. What I meant was that I didn’t want him to be too stressed out on the trip.. you know.. pull your hair out type thing.. but obviously the way I said it… led him to turn and say “hey!” .. in the “that-was-very-rude-why-did-you-say-that” voice….. I don’t know how these words come to me but… they do…

His wife was with him at the time and she didn’t seem to understand what I meant either.. they both thought I was just mocking his baldness…I never saw him again and I always felt guilty about that.

Please give me your foot-in-mouth moments? I have a couple more… somehow I say the wrong things…