Fun (yes.no.maybe)

So, my question for the universe. What is fun? What do you do for fun? I’m trying to figure out what I like post-university. However, someone very wise said to me today that you are the same person, just with more stuff in your head. Still, what was fun before that?
And, to top it all of, isn’t this a question of enormous privilege anyways? I’ve still got a lot of stuff in my head…