Why does my baby cry during certain songs?

I have a 1 1/2 year old daughter who jams to Beethoven and Mozart, and even jams more to Metallica but when she hears either the songs "go to sleep little baby" or "you are my sunshine" she immediately starts crying sadly until the song ends. It happens every time. I understand that it could be psychosomatic but I really can't understand this since she's never heard the songs when she fell down or bumped her head. She's really a happy baby overall. It's really strange. Any ideas?