The important thing is that the host will always show you a goat, meaning the old way the other hours bed the car old if you kist so happened to pick it the first time.

Take the situation to the extreme and imagine a hundred doors, and after you pick a door, the host opens 98 doors, all of them with goats behind them. Now which seems more likely, that you chose right the first time, or that the other door has the car?