I tend to leave other players alone for the most part. If I see a marker on my minimap i'll expand it to see if they're following me and prepare to fight but unless i'm hit with a bullet or crashed into I'll leave them to it.
Sometimes when my friends head into a clothes shop or Ammu-Nation I park up my car. get out and roam around outside. If a player comes up and tries to get in my car I won't do anything but If they shoot it I'll kill them.
Sometimes I like to kill cops chasing other players and drive off just to be that cool guy who saved you