In my late twenties I spent three full years smoking weed everyday. I didn't build a career in my 20s, I just fucked around because I didn't know what I wanted to do with my life. I smoked weed and partied. I had a long-term relationship in my 20s, but we broke up and at 30 I was single again. I was thoroughly lost. I slept on a friends couch for 5 months in a row. All in all, not a very bright future, right? Wrong!
I'm 35 now, I quit my job & moved abroad, became an independent web developer, met a wonderful woman who's 5 months pregnant with our firstborn, I've been asked (!) to lead the development team of a highly rated startup and have been making more money than any of my peers for the last few years... So you know: things can change. It's not a strict requirement to spend your 20s all serious - even if you don't, you can still be successful.
One of Britain's wealthiest men had a similar experience in his 20s. He didn't get started or even have a bank account until he was 30: http://en.wikipedia.org/wiki/Duncan_Bannatyne
I'm 35 now, I quit my job & moved abroad, became an independent web developer, met a wonderful woman who's 5 months pregnant with our firstborn, I've been asked (!) to lead the development team of a highly rated startup and have been making more money than any of my peers for the last few years... So you know: things can change. It's not a strict requirement to spend your 20s all serious - even if you don't, you can still be successful.