Advice for your 20 year old self

A while ago, I had the opportunity for a night on the town with a group of people who have had much more experience in life than I have, both in years and in business.  After a few drinks, the conversations turned to the best way to live one's life, and every person I talked to, while generally happy, hadn't figured out the answer for themselves.  So I proceeded to ask each person what advice they would give to their 20 year old self.  Most of them interpreted this as me asking them advice for myself (I was much older than 20 at the time) and made excuses highlighting the differences between themselves and me as to why their answer would not be pertinent.  Insisting that I was talking only about them, and what advice they would give to their 20 year old selves, most people were baffled, or gave vague financial advice.  Nobody knew the answer to this question, and had nothing substantial to offer their 20 year old selves.  To their credit, we were drunk and I threw this question at them out of the blue.  This is an important question to contemplate however as it allows one to look back on the past with 20/20 vision and think about how to improve, and to pinpoint what really matters.  What advice would you give to your 20 year old self? (note this applies even if you are younger than 20).  Leave a comment below so we can read an answer that will benefit us both.