i've thought of this also...i did some studies on the human brain, blah blah blah, and that the reason music kinda sucks when you think too much is because your using your right side of your brain, instead of your left. (right giving you analyzing skills, etc, left giving you creativity). I've also found that if i'm playing by my self, i get more angry then if im jamming with people. this is probably just do to a state of mind thing, but who knows?