One moment that particularly comes to mind is when Macbeth and Banquo discuss the witches' prophecies and whether they could be true or not. If Banquo had possessed more perception, he might have paid more attention to the fact that Macbeth seemed mightily interested in the possibility of the witches' prophecies being true. At that moment, Banquo should have pulled his ally to the side and convinced him that the witches' message was more mischief than anything else. He needed to look Macbeth in the eye and say, "Look, it may be fun to think about the possibilities, but those crazy old hags are just teasing us." Had Banquo been more earnest about denying the prophecies or their potential of being realized, then Macbeth might not have become obsessed with his own sense of ambition.