Facebook’s chief operating office and the author of Lean In, Sheryl Sandberg gave a moving commencement speech and spoke about the sudden death of her husband Dave Goldberg on a vacation last year. She addressed a core theme of the optimism way of life: Resilience in the face of struggle and loss. “You are not born with a fixed amount of resilience. Like a muscle, you can build it up, draw on it when you need it. In that process, you will figure out who you really are—and you just might become the very best version of yourself,” Sandberg said.