Most of us in the baby-boom generation were raised by full-time mothers. Even as recently as 14 years ago 6 out of 10 mothers with babies were staying at home. Today that is totally reversed. Does that mean we love our children less than our mothers loved us? No but it certainly causes a lot of guilt trips.
Also to be honest my dad wanted me to be an athlete. And I think all sons want to prove something to their dad. So now aged 35 I want to see what I can achieve physically.