Interesting talk by a well-spoken and insightful guy. He talks about the demoralizing effect of seeing no effect from your work. He describes his experiments designed to show how important a sense of meaning and progress is to continuing to do good work.
The good news: it takes little conscious planning, and little effort, to motivate good work. The bad news: it takes far less consciousness or planning, and no effort whatsoever, to demotivate.
Twenty minutes, interestingly spent.