Macbeth's ambition is the very thing that ultimately leads to his downfall. His insatiable desire for power and recognition blinds him to the consequences of his actions, causing him to make increasingly rash decisions in the pursuit of his goals. His willingness to do whatever it takes to maintain his grip on the throne, including murder and deception, ultimately leads to his undoing. In the end, it becomes clear that his ambition has consumed him entirely, leaving him with nothing but regret and despair.