Well, mine isn’t nearly as funny as everybody else’s, but when I used to play (flute) in the community orchestra, the conductor would stop us every 20 bars or so and tell us how to play it better. I think we only managed to play the pieces all the way through in one go at the dress rehearsal!
Here’s one from a friend of mine (oboist). A conductor was doing a choir and orchestra piece. While rehearsing the choir specifically she stood in the middle (between the choir and orchestra). The concertmaster gave the downbeat so everyone could play.
It’s a standard orchestra, right? (yes).
She kept asking (in her particularly snooty british accent) for ‘More Saxophone!’
Yes, it’s an episode where the station personalities have to come up with jingles for their shows, and of course Frasier goes overboard, composes a huge piece, then hires a chorus and orchestra for it and unleashes his inner Toscanini.