That's a good piece of advice. I went from being a carefree teenager to a highly "efficient" grown-up who's always asking how I can get more by doing less. I mean, that are obviously perks in setting goals and being time and money savvy, but in the process I've lost the child in me -- the child who wonders and has multiple hobbies. I couldn't even sit down to play a game without feeling like I was wasting my life away.
So yeah, like you say, fulfilling one's responsibilities is important, but don't go crazy chasing after the next shiny thing. It's perfectly fine to want to do nothing and just enjoy ourselves sometime.