I am seen 2 in my time.
One was when a female powerlifter was doing squats, and a guy came up behind her and made motions like he was fucking her from behind, with a few guys all around laughing.
After her set, she was so mad that she picked up a 2.5kg plate, and whacked it across the head of the guy who was doing this.
The second one was between 2 powerlifters. One a national champion, and the other an outlaw bikie dude who was also a powerlifter (although not as good, and primarily a guy who like to bench big and have big arms). They had a dispute (can't recall what it was over now), and after a few harsh words were exchanged they agreed "to take it outside". The bikie guy won that one.