It's a strange sliding scale.
Guys in their teens want to be in their 20s.
Guys in their 20s would like another shot at achieving some of their sporting goals not achieved during their teens.
Guys in their 30s would like to be in the condition they were in during their early 20s.
Guys in their 40s would like to be free of the accumulated injuries that they didn't have when they were in their 30s.
It seems like when guys are over 50, they would like to be the age that I am now. Financially stable, secure job, most of the child rearing thing over with (except for me, my little guy is 3).
Life is pretty good. I wouldn't change a thing.
Birthdays (mine) suck, though!