Anytime another magician performs around me, I study everything about the trick they do and how they present it. I don't do this to tear them apart, but I believe you can learn something from just about anyone regardless of how well they perform. If they do things that I don't like, I make a point of staying away from that in my own performances. If they do something (trick-wise or presentation) that I like, I will find a way to use whatever I can and adapt it to my own style and personality.
If I'm the one performing, then I see that as a chance to pull out all the stops and not give them anything to talk about. If you are nervous around other magicians, then you need to perform more around other magicians. If something goes wrong during a performance (which should be rare if you were ready to peform the effect), a spectator will probably say "I saw that" or "I saw how you did that", ect. But another magician who is true to the world of magicians, would say "here's something you might do to make that trick better". Or something like that. I think you get the picture.
I do know what you're talking about though. When I was much younger, I viewed everything as a compitition between magicians. For some of them it is. But for many of us, we're there to help each other in any way we can.
I definitely agree. When a magician is in a crowd, its just good to clap when he finishes and act amazed or at least entertained.