$PI I once asked a friend what kind of life they would most want to live if they truly achieved financial freedom.

He said he'd just want to go to university every day with a backpack and audit classes.

Listen to white-haired professors lecture on mathematics, philosophy, and art—things unrelated to making a living, yet truly fascinating.

Sit in the back row of the classroom with wind drifting through the windows, someone speaking slowly at the podium, while he quietly listens and carefully takes notes.

Not for grades, not for a diploma, not for promotion, and not for publication.

Only for that moment of sudden epiphany: ah, so that's how it is.

After class, go to the cafeteria for a hot meal, and while walking, ponder how much more he understands about the world today.

Even now, I believe that this is probably the cleanest, most grounded happiness one can experience in a lifetime.