big burst of cortisol is what we call “fear.” Small drips of cortisol are “anxiety” or “stress.” These bad feelings tell you you’re in immediate danger of pain, and your cortex tries to figure out what the danger is. Your reptile brain can’t say why it released the cortisol. It just responds when electricity flows down a pathway you connected in the past. You built those pathways from real experience, so the danger feels real to you. You want to avoid stress, but you want to avoid harm even more