Been in more than I can remember when I was a younger lad. I grew up in a hick logging town in Northern B.C., and there were three types of people. Bullies; those who got bullied and took it; and those who got bullied but wouldn't take it. I was the latter.
Won a few, lost a few.
And I spent a couple of years working as a doorman at two clubs. Worst job I've ever had, but the cash was good. I'm not a huge guy - only about 5'11", and a pretty solid 215 pounds - but because I was much smaller than the other doormen, drunk idiots would try showing off by picking fights with me. That grew real old, real fast.
And aside from one silly altercation at my bachelor party, I haven't fought in years. Right about now, the only thing that would make me strike someone in anger is if something happened to my wife or my girls. Then all bets are off...