nostalgia and endorphins

Can anyone explain to me the reason why something can feel so wonderful just because it is something that was a part of our past?

It seems mysterious to me. Is it the comforting aspect? It is because we romanticize the past so we remember the pleasant memories and the music gets associated with those memories and we feel happy when we remember them?

So today, I am going to spend 10 minutes listening to old songs while I fold laundry.