Things like Sometimes you just shut up and say "thank you."
Sometimes you can't just wait to be noticed, you have to raise your voice. Sometimes your ideas are good even if others shout you down. Some people are just plain idiots and asses.
But the hardest thing and most important thing I have had to learn is that it all works better if we all share focus.
It isn't always about you.
Relationships, Stage comedy, the community you are a part of (like, say, filk or a concom) all work better when you play them as an ensemble, not Prima Donna and Chorus.
Some people need to get over themselves sometimes.
I'm just saying...