There should not be any story behind the music. A 'story' can change our perception of the music. The music should exist on its own. I don't want to hear that the composition was the result of the author's desperate desire to get a divorce or as a warm tribute to his or her pet kitten, or... A composition should touch on universal emotional reactions, not programs. The only exception might be 'multi-media' compositions, such as music/ballet, or music that is joined to lyrics.