I laid a whoopin' on a person who broke into My Jeep many years ago. Caught him red handed inside going through my glove box. Felt bad about it afterwards because the guy was younger and rather skinny, and didn't really stand a chance.
Meh, I wouldn't feel too bad. Anyone that breaks into someone's house or car deserves a whoppin'.
Even in a slum area, the very worst thing you can do as a law-abiding adult is get into an actual fist fight. It's not hard to kill someone with a punch to the right place, or get knocked out and have even worse things happen to you.....
The bottom line is that there is no time or place for a fist fight. Maybe in some bar brawl.. but in day-to-day life (walking dogs, going to store, etc) if someone instigates a fight with you, you'd better have some backup plan other than your fists.
Blunt-force weapon is a good start. I don't think you're allowed more than a few blows below the head in our great country though... Otherwise you get thrown in jail for assault and battery, etc.