It's an old and tired adage by this point but it seems it falls to me to be the "time spent doing something you enjoy is never wasted" guy this time around.
Old and tired is OK, but this one to me looks invalid too.
I can't say of anybody's personal goals, but "time spent doing something [one] enjoys" is often wasted.
First, because every time you spent has an opportunity cost.
Second, because empirically peoples' future self often doesn't have the same priorities, and occasionally finds "time spend doing something they enjoyed" wasted and a bad choice.
How many regret e.g. wasting too much time gaming when they should have been e.g. studying or practicing, when they turn 25 and have nothing to show for it?