At one of the folk clubs we go to in our neck of the woods, there is a really good classical guitar player who is a bit of a perfectionist -he can quieten a noisy pub with his playing, although being a nylon stringed instrument it's not loud.

When he makes a mistake, which is most times insignificant and would not be noticed, he shouts out "Oh, Bugger" very loudly, so much so that everyone else has started doing this when they screw up.

At a school I used to teach at there was a really eccentric classical music teacher. Apparently he also used to play the church organ for Sunday services, but when he played a wrong note would say "Oh, Shit!" in a very audible way.