The best single example of this is in Act III, Scene IV, in which Hamlet confronts Gertrude. Although the scene includes the accidental stabbing of the kindly, bumbling Polonius, his death is almost an afterthought. What is more powerful and startling is the confrontation between mother and son. Gertrude exclaims, 'O, what a rash and bloody deed is this!' and Hamlet replies, 'A bloody deed! almost as bad, good mother,/As kill a king, and marry with his brother' (1002). In Hamlet's reckoning, his mother is implicated in his father's death, whether she knew about it or not, and her act of marrying her brother-in-law is much worse than his of killing an innocent man.
The psychological brutality of the scene is more devastating than the physical violence. As she becomes aware of the truth of her son's accusations, Gertrude begins to dissolve. She cries, 'O Hamlet, thou hast cleft my heart in twain' (1003). He, perhaps realizing the impact his words have had, finally then acknowledges the dead body at his feet and bids her good night, encouraging her not to compound her sins by continuing to be a wife to the man who murdered her husband.
Once Hamlet has accepted his father's charge to avenge his death, he begins a campaign of violent destruction that he seems unable to stop. Yet every step of his revenge, even this scene in which he reveals the truth to his mother and convinces her to give up her wifely duties as part of the vengeance against Claudius, gives him no comfort. Shakespeare shows clearly that violence breeds only violence and misery. Among Hamlet's last words to Horatio as he is dying is the caution to remember the pain that his acts have caused. He asks, 'Absent thee from felicity awhile,/And in this harsh world draw thy breath in pain,/To tell my story' (V II 1017).