They discuss motivation and incentives. Very enjoyable conversation. If anything, it is a little too fast-paced. One point is that people seek autonomy, mastery, and purpose. I think that is very true in people's avocations, or hobbies. I think, though, that finding those in your job is something of a luxury.
I suspect that a big reason that mathematics took over economics is that it gives you a sense of mastery. Indeed, it may give you a false sense of mastery. As you learn mathematical economics, you realize that you are getting really good at doing something that only a small group of people is able to master. And you get the sense that because you completed a mathematical proof that you accomplished something. It is very seductive.