I'm pretty lucky. The guys I fly with are friends, and we rarely end up sharing the field with many others.

When I'm around people I don't know as well, I try my best to talk to them a bit. Not just while flying. Establish a rapport, and everyone is more likely to communicate when something needs to be said and much less likely to do something unkind or unthinking.

That said, I've yelled at a couple of guys who have started doing jackass things while I'm flying. The old man who can barely hover his helicopter, and decided to try that at the end of the active runway while I was flying? I really don't care if he thought I was a donkey. People who don't yell out what they're doing when you're in the middle of flying and don't care to crank your neck around to see them dicking around behind you? Same deal. Some people are just stupid. That's not their fault, and it's not my fault when I remind them of it.