Where does stress come from? Financial pressures? Looming deadlines? Conflicts at work or at home? For more than half a century, we’ve been told that stress comes from circumstances like these, that it’s a by-product of our ancestors’ fight-or-flight response to danger, and that the best we can do, given the fast pace of life today, is to breathe, try to relax, and accept that life is hard. All of this, according to Andrew Bernstein, is wrong. Spurred by the death of several family members when he was young, Bernstein began a quest to understand the real dynamics of stress and resilience. He eventually realized that stress doesn’t come from your circumstances—it comes from your thoughts about your circumstances. More specifically, stress is created by a particular kind of thought that humans happen to excel at.