Today on The Gist, Gretchen Rubin explains what self-mastery has to do with happiness. She’s the author of The Happiness Project. Her new podcast, Happier, is part of Slate’s just-launched Panoply network. For the Spiel, Mike and Veterans Affairs Secretary Robert McDonald both lie to the homeless. Today’s sponsors: Stamps.com! Sign up for a no-risk trial and a $110 bonus offer when you visit Stamps.com and use the promo code THEGIST.