Macbeth's fatal flaw is his overwhelming ambition, which is driven by his desire for power and status. This ambition is what leads him to commit murder and ultimately brings about his downfall. Throughout the play, Macbeth becomes increasingly ruthless and paranoid, as he seeks to maintain his position as king. This is evident in his soliloquies, where he acknowledges the destructive nature of his ambition. While Macbeth does have moments of hesitation and doubt, such as his initial reluctance to kill King Duncan, he ultimately gives into his ambition and carries out the murder, which shows that indecision is not his fatal flaw.