Oops, I Accidentally Wasted My Entire 20s (And I Feel Fine)

Why is this is acceptable in your 20s? Why not sleep/drink/waste your way through your 30s or 40s?

"Know yourself" sounds too much like "Don't just do something, stand there!" I'd rather learn by doing than spend months in limbo figuring out who I truly am. Then you really have stories to tell that become part of who you are.