An in-depth look at the illusion of certainty in trading and its impact on decision-making. Analyze how the brain simplifies complex markets through the need for cognitive closure, and reveal the risks caused by over-reliance on predictions, backward-looking bias and absolute language. Wmax behavioral finance series guides investors to establish probabilistic thinking, record counterfactual logs, fight against irrational biases, and maintain sobriety and professional decision-making in a financial market full of uncertainty.