[Nursie]

This neglects that for many people your 20s are also when you're at your most active, most sociable and all-round most alive.

To me an over-emphasis on 'investing' during this period is the real waste.

[philwelch]

Activity and sociability are exactly the resources you use to create your investments, by achieving real accomplishments, building your skills, and meeting the people who will become your lifelong friends. Hell, you should even have a lot of fun--having good memories and stories to tell are an investment, too. But bias yourself towards things you'll want to have done later, not just things you want to do now.