Arthur Brooks has a confession to make: “I’m not a very naturally happy person.” He tells me this one May morning in the lobby of the Ritz-Carlton, Half Moon Bay, thirty miles south of San Francisco, where he’s come to emcee The Atlantic’s two-day “In Pursuit of Happiness” festival. Brooks has spent the past twenty years training himself to overcome his less-than-sunny disposition and become a genuinely happy person, and now some 200 people have paid $700 to attend this conference, many flying across the country, because they believe he can help them do the same...