When I was younger my parents would frequently comment on how much I worked and ask why I worked that hard, and I'd usually reply something like "because that's what I need to do".

Maybe they had a point and I didn't need to work quite as hard as I did, but it was also true that working the 8 hour days my dad did wasn't going to cut it. I didn't think about it at the time, but in retrospect it was a sign that I was coming up in a different world than they did.