It would be easy for an angry Hamlet to take revenge. But, at first, he really isn't sure who did what? As one critic also states, Hamlet is filled with references to the need for rational control of emotion. We have to remember that from early childhood, Hamlet, as Prince of Denmark, was brought up to one day be King. His father tended to ignore him, and yet his mother was overpoweringly smothering, and giving him up to marry Claudius: "She married. O, most wicked speed.." (Act I, Scene 2, line 156). He learned to control his anger as well as his joys, it would seem. We can see that most "royals" even in modern times, have to hold to a certain demeanor that is supposed to "elevate" them in appearance, at least, as being "different".
The situation is something Hamlet has neither thought of, nor faced. He really has never had to think for himself, even when he was sent off to school there would always be courtiers and servants around to do things for him. Now, his world has collapsed and he is not angry at first, just sad and lost. "How weary, stale, flat, and unprofitable, Seem to me all the uses of this world!" (Shakespeare Act I, Scene 2, lines 133).
Let us suppose for a moment that Hamlet, having heard the Ghost tell him his uncle murdered him, goes off and kills Claudius. Then what? We have to assume that Hamlet is not yet ready to be King. Neither is the country ready for a second death. There would be political and military uprisings. And, we also have to remember that there is an army ready to invade Denmark. Would a quick murder of the murdered solve anything except to satisfy Hamlet's revenge?
Of course, there are those critics who will say that there really WAS no Ghost. That it was all imagination. That it was an excuse to give Hamlet some sort of "comfort" or relief from his grief. Ghost or no, this encounter seemed to send Hamlet over some sort of sanity edge. Why does he delay? Critics suggest...