Who gets the credit for a quality movie?

I'm a frustrated writer but I'd have to go with director here. A bad director can destroy a good script and salvage a weak one. Did you ever see any of the Greenlight Project? They kept raving about how good that girl's script was but the director failed to see her vision. The director is the magician behind it all. If he can't pull it together even with a strong script then the result is garbage. It's got to be tough.