Conducter

A conductor was having a lot of trouble with a drummer. He constantly
gave this guy personal attention and much advice, but his performance
simply didn't improve. Finally, before the whole orchestra, he took a
critical jab at the drummer,

"When a musician just can't handle his instrument and doesn't improve
when given help, they take away the instrument, give him two sticks,
and make him a drummer -- which must be why you play the drums."

A stage whisper was heard from the percussion section,

"And if he can't handle even that, they take away one of his sticks
and make him a conductor."