I just remembered this alarm clock my grandparents used to have, which played some sad melody, and I would sneak in their bedroom and listen to it, even though it made me feel melancholy. And wondering at the same time why should I want to listen to something that was so harrowing and sorrowful (a music box rendition of probably some musical song... might not have such an impact on me today :D ).

"it surely must all be conditioned" > I don't think that's true, there are certain universal similarities in speech tones and for example melodies to sing to kids to make them sleep are apparently easy to recognise across cultures. There was a study on that, I need to dig it up!