I want to open with certain unavoidable caveats, just in case anyone leaps first to any assumptions about what’s being said here. No one is saying you can’t have fun.
Let’s make that damned clear.
No one is saying you can’t have fun. In fact, we’re saying you must have fun. Have fun! That’s an order, Ensign!
But fun is… a thornier thing, all the time, beyond just whether or not you are having it.