"The expression I use: Pain + Reality = Progress. Whenever I would have a painful mistake, I started to view that as puzzles that would give me gems if I could solve the puzzle. So, it made me thoughtful - what should I do differently next time? That was the puzzle. And the gem was some principle for handling the same thing when it came along again, and then I would write it down. And by writing it down and referring to it, and also being able to show it to other people so that we could agree that that was a good way of handling that thing - that was very, very powerful."