I remember the feeling of being 12 or so and lamenting that I no longer enjoyed the same kind of play in the (literal) sandbox any more; a bit of sorrow at the loss of a source of joy in my life that I had grown out of. It was an interesting realization that growing up means changing desires and priorities and that I should expect to reach plateaus where I would need to pick a new direction to go in. I've always followed my personal interests and hobbies since then; there seems to be a fairly broad line between nonproductive hedonism and goal-driven productivity where there's plenty of room for personal satisfaction without risking an identity/purpose loss when big goals significantly drop in priority.
Working on a particular goal to exclusion of all else sounds like quite a shock when that's no longer a driving priority.
Working on a particular goal to exclusion of all else sounds like quite a shock when that's no longer a driving priority.