It's no surprise that our fast-paced, overly self-analytical culture is pushing many people-especially women-to spend countless hours thinking about negative ideas, feelings, and experiences. Renowned psychologist Dr. Susan Nolen-Hoeksema calls this overthinking, and her groundbreaking research shows that an increasing number of women-more than half of those in her extensive study-are doing it too much and too often, leading to sadness, anxiety, and depression. She challenges the assumption-heralded by so many pop-psychology pundits of the last several decades-that constantly expressing and analyzing our emotions is a good thing.