Much of the time, we have little control over events that negatively affect our lives. We do, however, have some say in how we react to our worlds being turned upside down. This hour, we’ll talk about how to think clearly and keep our feelings in check during a crisis with Harvard Medical School psychologist Susan David. She’s the author of “Emotional Agility: Get Unstuck, Embrace Change, and Thrive in Work and Life” (Avery).