What does Macbeth's reaction to the witches suggest about his character?

Macbeth is quite taken aback by the weird sisters. Initially there is a sense that Macbeth does not take these hags seriously but when they begin listing off his promotions, Macbeth is all over their "predictions". Certainly this suggests that Macbeth likes what he hears. He is seemingly loyal to Duncan but is easily swayed by the power of suggestion, no matter how preposterous. When Macbeth finds out he is Thane of Cawdor, his little brain starts running overtime. The seed of suggestion planted, Macbeth is considering fulfilling the rest himself. Even Banquo notices this, "Look, how our partner's rapt". We can safely say that Macbeth's loyalties are very transient (He forsakes L. Macbeth in a similar fashion much later in the play). He is an obsessive personality who is unable to see the boundaries of his own ambition and sanity.