The first time I really thought about the notion of joy was after reading Zadie Smith’s 2013 essay, “Joy” in the New York Review of Books. Smith described joy as something distinct from pleasure. Joy was a “human madness” and “strange mixture of terror, pain and delight.” I was familiar with Daniel Gilbert’s science of happiness. And I had considered myself an expert of whimsy, having been deeply influenced by a Polish roommate in graduate school who insisted we celebrate every victory, however small, with champagne . . .