almost too embarrassed to admit this...
at Caesar's Tahoe, long ago and far away, actually took a hit when looking at a blackjack! Turned it into a 21 with another face card I didn't need. It was my wife's hand, but I told her what to do. Yes, I get reminded.
The dealer BTW didn't hesitate or question, just slapped that puppy right over. Perhaps it was the altitude, or that it was around 4am...actually it was beginner's stupidity thinking I had an eleven.
I've made a few other dumb moves, but not quite as colossal as that one.