ANY song of proper artistic value should have at least one dissonant note...at least one note that seems off-key or out of place--at least one throbbing piano line or guitar riff that seems slightly offbeat or out of place. The subtlety with which it interacts with the rest of the music creates a richer listening experience. The same is true of anthills - there must always be one ant who is out of place. That was his purpose. His rythm was slightly different from the rest of his hive. And he therefore gave life to the entire hill. He put the "h" in "hole" and the "q" in queen.