What advice would you give your twenty-year-old self, and what should they ignore?

Always remember that it's much easier to apologize than to get permission. In this world of computers, the best thing to do is to do it.

So any student who wants to get into psychology, right now the students are like lemmings. They say, “Well, it’s popular to study brain science, I’ll do that.” Or, “It’s popular to do neural networks; I see 30,000 people doing it, it must be good.” And my advice is if a lot of people are doing it, don’t waste your time.

Your time is limited, so don't waste it living someone else's life. Don't be trapped by dogma — which is living with the results of other people's thinking. Don't let the noise of others' opinions drown out your own inner voice. And most important, have the courage to follow your heart and intuition. They somehow already know what you truly want to become. Everything else is secondary.

My grandfather looked at me, and after a bit of silence, he gently and calmly said, “Jeff, one day you'll understand that it's harder to be kind than clever.”

Life doesn't offer you the perfect opportunity at the perfect time. Opportunities come when you least expect them ... Rarely are opportunities presented to you in a perfect way. In a nice little box with a yellow bow on top. ‘Here, open it, it's perfect. You'll love it.’ Opportunities -- the good ones -- are messy, confusing and hard to recognize. They're risky. They challenge you.

Learn by doing, not learn first, then do. The way you discover what it is you like to do in life is by doing first, then learning about it.

Fearlessness means taking the first step, even if you don't know where it will take you. It means being driven by a higher purpose rather than by applause.”

So take the time to find the thing that excites you more than anything else in the world. Not the thing your parents want you to do. Or the thing that all your friends are doing. Or that society expects of you.

Getting rich slow isn't actually slower. It's slower in year one, but it might be faster in year seven.

I think fear and fear of the unknown and perceived failure is what holds people back. For me, I am more scared of complacency than having something not work out. I'd rather take a leap of faith and fall than stand on the edge forever.

My last piece of advice is the one I could have used the most. It took me a long time to learn. And it is this: You are not a slacker if you cut yourself some slack. When I was your age, I didn't believe in vacations. I didn't believe in weekends. I pushed everyone around me to work very long hours. In the early days of Microsoft, my office overlooked the parking lot—and I would keep track of who was leaving early and staying late. But as I got older—and especially once I became a father—I realized there is more to life than work. Don't wait as long as I did to learn this lesson.

Do a deep reflection on what exactly went wrong and write it down. Please don't do that lazy analysis where you just blame government, the economy, the markets, fundraising etc. It might have been a contributing factor and you should reflect that but please do that uncomfortably deep and introspective work of figuring out where *YOU* the founder went wrong.

The challenge of a big, over-arching vision is that it's hard to know where to start. And your biggest opportunity will change from year to year. Technology changes. Competition changes. You change. My advice: Just start. Find a single unmet need that nudges the world closer to where you believe it's going. And if you hit a dead end, pivot.

I wish I had known how to “manage up.” I wish I had not believed that my work would speak for itself; the working world requires a bit more than that.

Scientists are people who are curious and want to pursue knowledge and pursue truth, and this still remains the most timeless and priceless value of a scientific career. My advice to an early-career scientist is to remain true to your passion and curiosity and that sense of mission to discover knowledge and uncover innovation. It's also very important to be using the tools of the moment, of the century. There are a lot of new tools to uplevel our own scientific research and scientific quest.