Oh the rolling function can be really useful by the way. Often you'll find idiots who'll try to run you over repeatedly until you die (often there's no stopping this if they've hit you once, as it takes time before you're stood up and back in control), if you manage to dodge their car you usually have an easy and very fulfilling kill lol
Maybe I've just been lucky, but I've honestly had more good encounters than bad ones. I always try to look not threatening when approaching someone (no weapon selected, don't run/drive in a way you would if you were gonna kill them). I've almost never killed anyone unless they killed me first, but if some douchebag kills me for no reason and ESPECIALLY if they camp outside a store/mod shop/safehouse and then blow me up or something, THEN I'll often spend 10 minutes hunting the prick down and killing him as many times as possible, which often results in them leaving the session
Last time someone killed me was two days ago, we were just standing beside each other and all of a sudden he starts shooting me. Fun part for me was that he was a total noob. He fled to the beach, I hunted him down and killed him. Where does he spawn? Beach. I proceed to run him over with my car and kill him 4 more times, all at the beach, before he's had enough and leaves
I like trying to make friends with strangers in freeroam, often I'll get into a random guys car and drive with him for a while. I'll get off when I'm bored and give him the Salute (select action from Select menu, press R3+L3 to activate)