--And don't get me started about bass players...
A: A drummer.
A cop sees two guys fighting. It turns out that they're a guitarist and a keyboard player. "What's the problem?" says the cop.
"We were coming off stage and this guy bumped my guitar so hard he knocked one of my strings out of tune!"
The cop says, "Is an out-of-tune string really worth fighting him over?"
Guitarist: "Absolutely! The lousy guy won't tell me which one it is!"
Q: How do you make a guitarist stop playing?
A: Put a sheet of music in front of him.