What's unintuitive about the Monty Hall problem is the difference between mathematical Monty and a psychological Monty. It is easy to imagine Monty almost only opening doors in case the guest choose the car, and not opening anything in case they choose a goat. So, when presented with the choice, a cautious guest will hesitate to change. If, however, the guest knows from previous shows that Monty will ALWAYS open a goat door, it is still mentally hard to change the cautious strategy.