Generate a full detail guide on the technique of 'decatastrophizing.' The guide should be clear and logical. It must include sections on: 1. Why our brains jump to the worst-case scenario. 2. A step-by-step exercise walking through an anxious thought and asking: 'What's the worst that could happen? What's the best? What's most likely?' 3. How to create a coping plan for the most likely scenario. Please include a strong disclaimer that this is an educational tool from CBT and not a substitute for therapy.