Nope, never really had to. I've had a few close calls though.

One situation involved someone being a little twat, and me letting him know damn well that he was being a little twat. After that, he kept saying he was going to kick my ass, but like two weeks later he apologized for acting like a twat.

Another time I snapped some dude with a towel and he threw a piss fit and told me if I did it again he was going to kick me in the face....so I did it again. A date and place was set up but he backed out of it at the last second.