well, there's a right place to show your stuff without much risk of offending anybody -- like jams, etc.
restraint is part of skill. that's why in music, there aren't only notes. there are rests as well. and the rests bring life to the notes. there aren't only fast lines, there are slow lines that give meaning to the fast ones.
music is sound rendered intelligently. silence is part of it. in fact, when silence is rendered intelligently, it becomes MUSIC too.
just like what the great chick corea said -- play only what you hear (in your head, that is). if you don't hear anything, don't play anything.