One of the things the Weird Sisters do besides prophesying Macbeth King, is make him feel insecure about his friend Banquo. They put him in a position where he feels like he is second in importance as there will be no one to inherit his throne; where any kind of lineal succession of his own is as unlikely as his the attainment of his peace-of-mind. Robert Greene says in his book on “Power”: “Always make those above you feel comfortably superior.” By the witches prophesying Banquo’s issue as future Kings and Macbeth experiencing such a tortuously ill-fated reign as King, Banquo does nothing but make Macbeth feel “uncomfortably inferior”. Like he is the butt of some sick joke that ultimately yields Banquo’s line all the rewards. The Weird Sisters know how to cause dissension and chaos to perfection and they do it so subtly with the careful choice of each scenario they put forth. Their words become Macbeth’s fears, and his fears become his actions, and his actions…his end.