The psychotic state of a person is not relative to a person being pushed into making a choice of getting mad or getting even. When you think about it, a person should not put pain onto their own shoulders. If somebody does something to them, then obviously that person didn't have the knowledge to think about the outcome of how bad it could hurt, so therefore REVENGE is the only key of getting back what you need.
Revenge is a persons way of releasing their anger or sadness back onto the person that caused them this state of mind.
In the story of Hamlet this is exactly what Hamlet does. He is driving himself crazy by holding in his anger. Insanity is driving by someone not releasing their feelings. Finally toward the end of the story Hamlet finally gets his revenge.