Geez, I spent a good portion of these years learning math and physics. I did take a couple years off to fuck around, but it was exceptionally unproductive fucking around; i.e. go to work, leave work as early as possible, call around to see who wants to go out for drinks and catch some djs. Repeat 730 times, then return to school. I did have some fun doing that, but I really didn't do much to "grow as a person" in my years away from school.
Being 18 was sort of cool because I had an incredibly hot girlfriend back then. Unfortunately, she turned into a speed freak when I was 19 (which is part of what inspired me to take some time off school).