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