We don’t always do what we’re supposed to do. We don’t save enough for retirement. We order dessert when we’re supposed to be dieting. We use the tickets we bought to a concert even though we’re sick. In other words: We misbehave.

That’s the title of Richard Thaler’s most recent book: Misbehaving: The Making of Behavioral Economics. If you’ve read Thaler’s previous book, Nudge, you know he’s an economist who studies why people don’t act the way traditional economists say they will. Thaler recently won the Nobel Prize in Economics for his contributions to the field of behavioral economics.

Shankar Vedantam sat down with Thaler in fall of 2015 for an event at the Willard InterContinental Hotel in Washington, D.C. In this encore episode, we bring you the best parts from that conversation: They talk about why it’s so hard to find a cab on a rainy day, how marshmallows can predict the future, and why the source of our money influences how we spend it.

Hidden Brain is hosted by Shankar Vedantam and produced by Maggie Penman, Jennifer Schmidt, Rhaina Cohen, Parth Shah, and Renee Klahr. Our supervising producer is Tara Boyle. You can also follow us on Twitter @hiddenbrain, and listen for Hidden Brain stories each week on your local public radio station.