"For I have a single definition of success: you look in the mirror every evening, and wonder if you disappoint the person you were at 18, right before the age when people start getting corrupted by life. Let him or her be the only judge; not your reputation, not your wealth, not your standing in the community, not the decorations on your lapel. If you do not feel ashamed, you are successful. All other definitions of success are modern constructions; fragile modern constructions."
~ Nassim Taleb
[Hat tip Scott Powell]