Sad Songs - the cure for heartbreak?

Whenever I've suffered from romantic problems, I'm always drawn to sad songs.  You know what I'm talking about - songs like 'All By Myself', the classic ballad that has been performed by countless singers since its original release in 1975.  I wish I knew why it happens because I'm actually not a sad person - perhaps if I were, it would make sense?  Infact, people usually refer to me as 'happy', 'cheerful' and 'gay' (but that's beside the point). 

Toni's shoulder tattoo was invisible to the naked eye

Time after time, whenever I've been feeling low, I resort to listening to those sad songs and despite the musical misery, I gradually start to feel a bit better.

I'm a firm believer in the power of music.  I've often forced myself out of a bad mood by listening to a classic Kylie song, but that doesn't explain the healing powers of sad love songs.