The point is, you can't keep doing the same thing and expect it to keep working.

Today the world lost a visionary leader, the technology industry lost an iconic legend and I lost a friend and fellow founder. The legacy of Steve Jobs will be remembered for generations to come. My thoughts and prayers go out to his family and to the Apple team.

Recognize that there will be failures, and acknowledge that there will be obstacles. But you will learn from your mistakes and the mistakes of others, for there is very little learning in success.

If you're happy, that's probably the most important thing. Everyone probably has their own definition of success, for me it's happiness. Do I enjoy what I'm doing? Do I enjoy the people I'm with? Do I enjoy my life?

Wearable devices are here to stay, and they'll only get more sophisticated and effective as they evolve. Until now, most of us have made our health and fitness decisions based on what we think we know about ourselves. Advancements in technology - wearables and otherwise - will eventually take much of the guess work out of healthy living.

The very thing you fear could be the best thing to ever happen to you

If you want to sustain excellence over a long time, you'd better come up with a system that works well. Anyone can sprint for a little while, but you can't sprint for forty years.