In moderate amounts, anxiety and depression can improve our focus and performance. That doesn’t mean that depression and anxiety are always useful. In large doses, they are debilitating. However, one of the most important truths about our minds is this: we don’t always have to obey them. In this episode, we hear from psychologist Dr. Shawn Smith, author of the audiobook "The User's Guide to the Human Mind: Why Our Brains Make Us Unhappy, Anxious, and Neurotic and What We Can Do about It." Dr. Smith talks about the biology behind anxiety and depression. He calls them “ancient tools”—tools that aren’t well-suited for modern times. While anxiety and depression can often be debilitating, in small doses, these seemingly negative feelings can actually help you excel.