Songs are as sad as the listener.

I'm reading this book by Jonathan Safran Foer called Extremely loud and incredibly close(click), and so far it is just wonderful. You just have to read it. The title is a quote from the book and here is some more:
Humans are the only animal that blushes, laughs, has religion, wages war, and kisses with lips. So in a way, the more you kiss with lips, the more human you are. And the more you wage war.
(And for even more; link.)