Tamla Kahn 'Hammeron' McMahon wrote
When you cock up in a band it is clearly not as obvious as when you are all by your lonesome I suppose...
Actually, it's not so much the worry about the screw-ups, it's more along what Bob was saying: you are the sole object of scrutiny on that stage. Just you. So instead of headbanging or scoffing a burger or chatting up a roadie or whatever, the audience is there listening to every word, every chord change and picking up every little facial expression.
It's that feeling of being under a microscope. It's the same when people single you out in a big meeting room with difficult questions (like, "who are you?") or when that pass is soaring through the air towards you in the dying seconds of a Super 14 final and Sonny Boy Williams is blocking out the sun ahead. That sense of sudden, intense scrutiny that magnifies all your self-doubts and makes your fingers feel like you left them in the fridge last night.
What repetition does in these cases goes beyond just building up motor skills: it starts to create that belief in yourself that you've "done this all before", and you came out of it. So while the nerves never really go away, you start to actually enjoy that tension and employ it in your performance. You start to develop a sense that you are worth listening to, that you deserve the opportunity to play up there for people, so the nerves become a chemical thing that's always there at the start, but stops hindering your performance, and may even enhance it.
Blah blah and stuff.
