I feel like happiness is not an absolute nor permanent state. It's ephemeral and relative. You go to a deli shop and your favorite sandwich maker makes your meatball sub just the way you like it. You eat that sub and relish every bite. You're happy and ... reasonably happy .... like Huell. Then later at night you get dumped by your g/f. Now you're sad and you experienced both on the same day.

I think the same way about sadness and depression. Not an absolute nor permanent state. You have your moments when you are sad and/or depressed and then you bounce back.

I think most people normally experience all these emotions on a cyclical basis.