People found it unusual to leave a job where you're the boss.

You're talking to investors - and investors, they look at you and they realize, you know, not every business they invest in are the founders or the people running it going to have every bit of skill - and I think they looked at me and realized, OK, this is a guy who's got a lot - I'm much older than the usual run of people they fund.

That economics and finance are often covered as technical subjects, sort of boring subjects, and either you already know a lot about it and you follow it, or you don't know much about it and you don't want to know.

The Bible is forbidding when you start to read it. The language is odd. The stories start and stop herkily-jerkily. The characters behave in inexplicable ways. It takes a little bit of time to get into the rhythm of the book. I found reading the first 15 chapters of Genesis very very difficult. Once I got past there, I loved reading, and found it very easy. When you get used to the Bible, it becomes thrilling to read (like any great book - I just had exactly the same experience with the Odyssey).

When you're writing for the New York Times someone reading it knows the topic better than you do and knows when you've messed up.

My buddy Alex Blumberg learned - he was very public about his learning process, and I know for a fact because we sat next to each other for many years, that he knew nothing about venture capital or seed rounds or "A" rounds or whatever you call them, and he had to really learn, like, pitch by pitch. He just screwed pitches up.

I do think there will be winners and losers in the 21st century economy.