Can a person who has devoted his life to mission (art, business, etc. — to each his own) have a full and happy life? Or it would be even more correct to say “Should she/he do it”? These questions…

Can a person who has devoted his life to mission (art, business, etc. — to each his own) have a full and happy life? Or it would be even more correct to say “Should she/he do it”? These questions…