Weeks after Dave died, Sandberg was talking to her friend Phil about a father-son activity that Dave would never be there to do. They came up with a plan to fill in for Dave, but Sandberg broke down crying: 'I want Dave.' Phil put his arm around her and delivered this now-famous line. Sandberg used it as the foundation for her entire speech about resilience, drawing on psychologist Martin Seligman's research about the three P's that determine how we bounce back: personalization (not everything is your fault), pervasiveness (one event doesn't have to affect everything), and permanence (the sorrow won't last forever). The phrase later became the title of her bestselling book, co-written with psychologist Adam Grant.