Esa-Pekka Salonen said it: "The composer is the chef and conductors are the waiters"

Well put by Esa-Pekka Salonen:

"The composer is the chef and conductors are the waiters. Both are totally honourable professions but we have to accept that if I conduct a piece by Beethoven, I'm just a waiter. I might be head waiter, but waiter none the less and I am there to make sure the food comes to the table on time and intact."