D, it's very rewarding. You have an idea, you write about it for a paragraph, and you realize two years, five years later, that it's you had a lot more to say. Each of your books kind of grows out of a small part of the book before. Do you have any regrets about things you wrote in your old books? I should not have discussed skin in a game. In antifragile i should have beenknown immediately that subject is important enough to be treated on its own. These are the things i regret now.