I have worked my arse off in my 20's. 10 hour workdays on average, and when I left my first employer, after 9.5 years, I got paid out 260 unused leave days (we had time-off-in-lieu for weekends).

On the plus side: this set me up financially for the rest of my life; I developed high skills and a good reputation; and the work was interesting in itself.

On the minus side: I lost touch with most of my school/university friends; had trouble maintaining relationships with girls.

Funny thing is: I am not sure whether I'd do it all again, or not... so I don't know what to recommend... sorry.