Payback

If you spend any time at a bar you'll eventually see someone get thrown out by a bouncer. Often it looks like they're getting taken out a little too roughly. 
I thought the same thing Saturday when two of my guys were running a guy out the door so fast I had to struggle to get the door open in time to let them out. He tried to stop from getting pushed out by grabbing the door. He ended up smashing into the door frame and still wound up outside.

When I asked the guys what the hell happened, it turned out this dude was asked to leave and threw a chair in response. The chair missed and hit some girl.

So yeah, when you see a bouncer being too rough with someone, there is a pretty good chance that he's just a power tripping asshole 'roid rage d bag. But ever once in a while the guy being taken out a little too rough has it coming.