I have made up my mind that the piece of music that is the ultimate expression of happiness is Sleep Walk, by Santo & Johnny!! Not like an exciting, atmospheric kind of happiness, but more like the kind of relaxed, calm you feel when you're a healthy kid living a carefree life and nothing is blocking you, like when you are hanging around fishing with a good friend. Honestly, nothing can beat the timbre of that guitar sound swelling with happiness.
Actually, it can be so happy that once the song ends, you snap back to reality and just feel miserable. What I'm trying to say here is that is something that occurs frequently and it's always how it goes