Markets are inherently unpredictable, and the difficulty with trading is accepting that hard work may not necessarily lead to results. This article analyzes the illusion of certainty and the temptation of chasing the Holy Grail strategy, explains the difference between probabilistic thinking and deterministic thinking, and the counter-intuitive trap that probability does not work like this under continuous profits and losses. It emphasizes the use of fixed entry and exit conditions, position upper limits and risk boundaries to respond to changing prices, making rules an anchor in uncertain markets.