What is one of the best investments you have made — of money, time, or energy?

Our business everyday is to make money for people. And I take it as seriously as doctors who are trying to cure cancer, because by giving people financial freedom, we allow them to do great things in their lives - from retire to send their kids to college, to buy their first house, to fund a business that they might want to start.

And so I ran. I ran up and down every court After every loose ball for you. You asked for my hustle I gave you my heart Because it came with so much more.

We need to have mentors. I think I've always been pretty shameless about seeking out people much smarter and much more experienced than me from the very beginning. Michael Seibel and other people. And the more successful I got, the more leaders I started seeking out, whether it was investors, or Sheryl Sandberg at Facebook, or I got the opportunity to spend time with Warren Buffett and he became a close mentor of mine.

When I started getting my first fan letters, I made a point to try to respond to every single one. The wins always felt that much more special because I knew I was making so many people happy. And losses hurt that much worse because I truly was invested in not wanting to disappoint those who supported my side. But more than anything, I always appreciated the fact so many fans invested their emotions in my performance.

I did boxing because I needed to channel the pain. I did karate because I was being beaten up and I wanted to be able to defend myself.

The reason I've been able to keep going for so long is because of how much I love my sport. I still haven't lost that drive. I'm still as passionate about my sport today as I was when I first laced up a pair of boxing gloves. I love preparing for battle and getting into that mindset you must reach when you're putting your body through torture in training camp.