<p>Why do Americans tip so much? What happened when Angie eliminated grading in a college course? And why did almost every pay toilet in the U.S.A. vanish between 1970 and 1980? </p>

104. How Simple Is Too Simple?

Research psychologist Angela Duckworth (author of "Grit") and tech and sports executive Mike Maughan really like to ask people questions, and they believe there’s no such thing as a stupid one. So they have a podcast where they can ask each other as many “stupid questions” as they want. New episodes each week. "No Stupid Questions" is a production of the Freakonomics Radio Network.

To get every show in the Freakonomics Radio Network without ads and a monthly bonus episode of Freakonomics Radio, start a free trial for SiriusXM Podcasts+ on Apple Podcasts or by visiting siriusxm.com/podcastsplus.