One time. I rarely go to bars, but it was my anniversary, and my husband and I went to see some friends at a Halloween shindig at a bar/pool hall close to a theatre where I used to work. Two random guys got into a shoving match, and fell on top of me on their way to the ground. However, the fall didn't end the fight. I was up at the bar to get a drink, and away from the people I was with, so I didn't have anyone to stop my temper or my instinct to immediately resolve a situation like that. So, I got up swinging to get out from underneath them, and dragged one guy off from the other so they would just walk away.
I was lucky, they were shorties, and so drunk they didn't really understand I was there, and very luckily, didn't understand I was something else to hit. I didn't get hurt, and the guys figured out quickly what happened, and were quick to apologize to me, and they peacefully let themselves be escorted out by my husband and his equally huge friend.
I am not one to start fights. But I have a temper that can potentially end in one. Especially in physical defense of another. I study martial arts, but I study a form based on peaceful redirection of energy. However, I also study a nasty guerrilla technique.
I enjoy physical contact, and "fighting" in a controlled environment full of people with love behind their fists is play to me. I was that way as a kid, too. I'll giggle my head off while pinned in a painful wrist lock, or wiping blood off my nose. I do have a serious belief in being capable of physically defending yourself and your loved ones, or even being able to protect a complete stranger in danger.
But it would be a serious risk to myself if I were to just willy nilly go start fights, and part of my training is an understanding that I do not put myself in dangerous or unpredictable situations like that. I understand that preparedness and premeditation are two different things.