Really sad music (like Barber's "Adagio"), triggers the Superiority Theory of thinking---that you are superior to the person doing the suffering. This also happens with other works of art----at least, after watching "Hamlet," you can say---well, at least my uncle didn't kill my father and marry my mother. So, you feel better. Same thing happens in comedy---at least I am not as geeky as the boys on "The Big Bang Theory." So,, I can laugh at them.