Sometimes, you go - you achieve a few things in life. I have achieved more career success than I ever experienced or that I ever thought. And I just realized, it doesn't make you happy. It's an elemental truth. It's so true.

Economists sometimes do try to reduce behavior to law-like predictability. But people respond differently to different primes, to different contexts even from one moment to the next. We possess multiple selves that are aroused by different circumstances.

For the Democrats, they're trying to avoid having the Sanders-Clinton debate over and over again. But, to some degree, they're sentenced to that debate. Clinton is much more embracing of the global economy and the international world order. Sanders and Warren are much less so. And they have got to figure out which side the party is on, if they're going to have a clear message. I think this is probably one you probably can't straddle.

If you grow up in a home where actions don't lead to predictable consequences, you don't develop strategies to control your impulses.

If Donald Trump is just tweeting about a union guy, then he's just being the bully we have seen. But if he uses the power of the presidency to back up some of those tweets and he's really, really coming down with a hammer on people he doesn't like using the power of the presidency, then we're seeing something very new and very different.

Friendship allows you to see your own life but with a second sympathetic self.

Of those two [Hillary Clinton and Donald Trump], I do think that the - right now, at least in my mind, the Democratic theme is eclipsing the Republican one.