As Noahcat mentioned, the stock markets are always closed on Good Friday.
As for singing at concerts - I agree that it is REALLY ANNOYING and rude. Who pays concert $$ to listen to someone in the audience sing? Of course, the louder the band the less it matters, but the band/singer is the attraction, not someone else in the audience.
...however, I wouldn't mind Sue Casey singing...
;-)
The worst experience I had at a rock concert was at a Joe Walsh concert, where the guy in front of us screamed non-stop and was mad that nobody would scream along with him. Not even an attempt at carrying a tune, just screaming.
The worst experience I had at a classical concert was at a performance of Bruckner's symphony #8, where the lady next to me fell asleep immediately and snored non-stop thru the whole concert. Back then I just sat there and seethed. Now that I'm older I'd probably wake her up and tell her to stop snoring. Her husband just ignored her.