I have 1 playlist of many, many songs (so many I don't have time to organize them)

my thought is usually: okay, I want some music on, let's see what my playlist comes up with and I let it run

sometimes (if I am in a particuarly good mood) I'll play all the latin songs (actually go out my way to find them, latin is my good mood music) but usually it's what's playing gets played.

what is one peace of music that you feel everyone needs to hear at least once in their lifetime?