That as well!
I'm lucky, working all my life in aviation but seldom as a professional pilot (more as a professional who uses the fact he's a pilot) I've been lucky enough never to lose my enthusiasm for aviation. But, I've seen many who have.
It's noticeable that you're far more likely to find 30++ year old aviation enthusiasts working in light aviation than in "heavy metal" - 10 years seems to beat the enthusiasm out of most in that area. Well on the civil fixed wing side anyhow, there aren't many unenthusiastic fighter pilots, and most helicopter pilots seem pretty happy as well.
G