To understand why calm, logical thinking is so difficult when you are anxious, it helps to go back a very long way. About 50,000 years, to be specific. Imagine two prehistoric humans. One is a relaxed optimist. He sees little point in worrying about anything. The other is anxious and alert, constantly scanning for danger. Now a threat appears. The relaxed optimist does not react quickly enough. The alert one survives. This is why you probably find yourself worrying more than feels reasonable. The tendency was selected for over thousands of generations. The people who worried enough to stay alive are the ones who had children. You are descended from them. Here is what this means practically. Your brain operates in three layers. The deepest layer, sometimes called the primitive brain, handles survival instincts and threat responses. It is fast, automatic, and does not think, it just reacts. The middle layer, the emotional brain, generates your feelings. The outer layer, the rational brain, handles logic, analysis and planning. It is slower and more deliberate. When you perceive a threat, the primitive brain reacts first, flooding your body with stress hormones before the rational brain has even registered what is happening. By the time you are trying to think calmly about a situation, your body is already in stress mode. This is why telling someone who is anxious to just calm down and think logically rarely works. The sequence of the brain does not make that easy.