I fell in with the cool crowd, cut more school than I attended, graduated with a grade .01 points above failing (I'd become an expert at doing the minimum), learned about recreational drugs and spent years in a drug-induced fog.
Later in life I decided to start applying myself and join the work force in IT and found myself utterly unprepared. Work was never hard, naturally, but it took me a long time to get up to speed on the normal, expected social interactions between co-workers.
In summation, while I like who I am and what I do now, I'm often plagued with pangs of regret at having wasted away all that time to rack up accomplishments and get something done with my life. There's still time, naturally, and I don't have a pressing need in life for anything more than I have, and things just move generally slower with a family involved.
Point 2: I, too, was a wunderkind -- and part of me regrets it. By age 12 I was hacking around the Freenets; by age 14 I'd tested out of high school; by age 16 I'd left home and was working for a well-known architectural institute; by age 18 I was running its computer department and my 3D visualisations and been featured on PBS and NHK, and exhibited around the world. But I was so busy being a wunderkind that I never took the time to be an actual kid. I was enormously serious: didn't goof off, didn't party, didn't kiss a girl until I was damn near 20. I wish I'd gotten an earlier start on all that. Honestly, there's plenty of time in life to rack up accomplishments, but youth is something that you only have once, and my advice to other wunderkind is to exploit the hell out of being young while you still can.
(Not that I would've listened to such advice myself...)