15 LESSONS FROM "THE DEFINING DECADE" BY MEG JAY 

1. Your twenties matter. 80% of life’s most defining moments take place by 35. 

2. Our personalities change more during our twenties than at any time before or after.

3. In almost all areas of development, there is a critical period, a time when we are primed for growth and change. The twenties are that critical period of adulthood.

4. The Strength of Weak Ties: Weak ties are the people we have met, or are connected to somehow, but do not currently know well.

Information and opportunity spread farther and faster through weak ties than through close friends because weak ties have fewer overlapping contacts.

5. Contrary to what we see and hear, reaching your potential isn’t even something that usually happens in your twenties—it usually happens in your thirties, forties, or fifties.

6. The post-twentysomething brain is still plastic, sure, but we will never see its ability to create so many new connections again in our lifetime.

7. Never again will we be so quick to learn new things. The risk is that we may not act now.

8. Twentysomethings who use their brains by engaging with good jobs and real relationships are learning the language of adulthood just when their brains are primed to learn it.

9. For work success to lead to confidence, the job has to be challenging and it must require effort. It has to be done without too much help. And it cannot go well every single day.

10. Two-thirds of lifetime wage growth happens in the first 10 years of a career.

11. In our twenties, positive personality changes come from what researchers call “getting along and getting ahead.” 

Being a cooperative colleague or a successful partner is what drives personality change.

12. We know that the brain has difficulty to keeping time over long, unpunctuated intervals.

13. We condense unmarked time. The days and years pass, and we say, “Where did the time go?”

14. People of all ages discount the future and favoring the rewards of today over the rewards of tomorrow. 

This “time inconsistency” is a human tendency, not just exclusive to twentysomethings.

15. The future isn’t written in the stars. There are no guarantees. So claim your adulthood. Be intentional. Get to work. Don’t be defined by what you didn’t know or didn’t do. You are deciding your life right now.