Honestly? My college years were perhaps the best. Loads of free time, surrounded by similarly directionless peers. A wonderful, but painfully adolescent time.
I squandered my 30's by working 80+ hours/week.
I'm now on the north side of 40 and having the best time of my life. I work a lot less. Last year I logged 3 full weeks of vacation with the guys, fly fishing in Alaska and Belize. Golf trips to Vegas, skiing in Canada. I also had 3 weeks of vacations with my family and several 3-day weekends away with my wife.
I will continue with this approach till my body or my money wears out.