Everyone has his or her own way I suppose. I have no problem with letting someone know when they're in the wrong, but I tend to do it in a non-threatening way.
If I see someone litter:
"Hey man, that's not cool, come on." in a disappointed tone. Usually works. Never had a fight ensue over this.
Someone bumps into me:
"Hi, can I help you?" in a warm tone with a smile.
Someone blocks me in:
"Sir, I may have to move my car and you're kind of blocking me in, are you going to be long?" same warm tone.
Etc...
The point is, there's nothing illegal or wrong about saying something to someone when they break a rule or a social norm. You do your best not to aggravate the situation and be done with it. I see too many people living in fear of the dreaded "if you say something to someone, and they turn and try to attack you, and you kill them, you go to jail" scenario. This is simply not true.
Show me a case where a person A began conversing with another over something in a non-violent manner, then person B escalated the issue with verbal threats and ultimately physical violence, and person A used a firearm or other weapon to defend themselves while the threat was active and imminent and they ultimately went to jail for defending their own life without having done something else illegal or wrong.
I'd like to see one. If someone litters, and you ask them to pick their trash up in a calm and civilized manner, and they bring physical violence or the threat of imminent harm to you, I don't see you going to jail without having actually done something illegal. If they cuss at you but in no way make a physical move towards you and you shoot, you'll be in a world of trouble. If they hit you and you shoot, and then finish them off with a head shot after they're down and the threat ceases, you will be in a lot of trouble. Aside from things like that, I know of no free state that will put someone in jail for defending their life against an attacker simply because the shooter struck up a conversation over a trivial or even controversial matter in a civilized and reasonable fashion.
Do I advocate the death penalty for littering? No, which is why you discuss the littering with words, not bullets. But when the litterbug escalates the issue by threatening harm or violence over littering, it becomes a matter of threat and intent, not littering (that was already addressed by the conversation). I do advocate the death penalty for perpetrating physical violence or harm onto one's fellow citizens.
