In both Hamlet and Macbeth, while the supernatural plays a vital role in the development of the protagonists, it certainly contributes much more to the drama of Macbeth in which there is a constant shifting and succession of things seen or imagined. This movement, indeed, greatly affects Macbeth; however, the predictions and appearances of the witches seem to affect him more than does the appearance of the ghost of Banquo. Nevertheless, when his murdered friend's apparition sits in Macbeth's place at the palace banquet, this appearance greatly contributes to Macbeth's paranoia. Seeing Banquo, Macbeth cries out,
Thous canst not say I did it. Never shake
Thy gory locks at me. (3.4.62-63)
While Lady Macbeth scoffs at him, telling him it is but the image of his fear, Macbeth continues to be affected by Banquo's ghost, declaring it stranger than a murder:
This is more strange
Than such a murder is (3.4. 98-99)
He challenges this ghost to reappear and calls it "a mere mockery." After the banquet, Macbeth becomes enraged and mad by the ghost's appearance, feeling that he has become so steeped in blood that he has no course but to continue,
I am in blood
Stepp'd in so far that, should I wade no more,
Returning were as tedious as go o'er.
Strange things I have in head that will to hand,
Which must be acted ere they may be scann'd. (3.4.165-169)
As the drama of Macbeth continues, Macbeth is driven by more by his paranoia of the predictions of the three sisters than he is affected by the ghost of Banquo.
On the other hand, the appearance of the ghost of King Hamlet plays an integral part in Hamlet. At first inciting his son to revenge, the thought of avenging this ghost then moves Hamlet only to anxiety and depression. Initially, Hamlet frets about whether he has actually seen this ghost, then he suffers from the dilemma of committing regicide; that is, Hamlet worries about killing Claudius unjustly and, therefore, being guilty of a serious crime.
This angst of Hamlet throws him into a maelstrom of madness as he considers suicide, becomes enraged at his mother, distrusts everyone, and drives his love Ophelia from him through disrespectful treatment and cruel words. But, overriding all of these emotions is Hamlet's depression which keeps him from real action, unlike Macbeth's raging madness and insane "vaulting ambition" which drives him to destruction. For, it is not until Hamlet measures himself against the "tender prince" Fortinbras, whose filial devotion and courage move him to action despite danger--
Witness this army, of such mass and charge,
Led by a delicate and tender prince,
Whose spirit with divine ambition puff'd,
Makes mouths at the invisible event,
Exposing what is mortal and unsure
To all that fortune, death, and danger dare,
Even for an eggshell. Rightly to be great
Is not to stir without great argument,
But greatly to find quarrel in a straw
When honour's at the stake. (4.4.49-58)
that Hamlet is spurred to his resolve to avenge the honor of his father,
O, from this time forth,
My thoughts be bloody, or be nothing worth! (4.4.87-88)
Declaring himself the prince, "This is I, Hamlet the Dane," Hamlet is spurred to action and duels Laertes in the final act, avenging King Hamlet by slaying Claudius. Thus, the effect of the appearance of his father's ghost has followed Hamlet throughout the drama.
Indeed, the responses to the ghosts that they see affect Hamlet and Macbeth differently.