I think it depends on the who and the where. Go punch some guy in Glencoe and see how that works out. The people who punch others generally have no assets, and not much of anything to lose. I agree, the criminal sanctions are a minor issue for those folks. But for people with something to lose, the civil consequences can be severe. I'd certainly be concerned about losing my bar license, I'd possibly lose my job even outside of work (definitely if I punched a co-worker). You can certainly be sued on top of that. So yeah, violence of that sort is pretty rare in the burbs. Draymond has a lot to lose and needs to control himself.
Lastly, as we learn in law school torts class, it's risky. You take you victims as they are. Guy has some rare problem and you kill him or put him in a coma, guess what, that's still on you.