I agree with what others have said, I'm sorry you encountered unfriendly people on the trail! I always try to say "hi" to anyone who's around me, even if behind, that'll help establish communication even if they're being quiet and not announcing themselves. I do think that you should yield to faster riders where appropriate, but they should have no issue stopping for you too if you're working on a tricky section (even if it's an easy section for them!).

the only time i was really buzzed by another rider was actually on a relatively easy trail, i was coming up a climb that had some jumps on it, and he was FLYING down it and made absolutely no effort to stop. My local trail is quite technical and I think it helps people be more aware of their surroundings, because I'll have to say normally i find people quite respectful!

good luck in anycase!