It is that he has no bona fide cause for revenge (one that he states) that makes this story so horrifying. By not identifying the cause for revenge, we cannot dismiss it as unworthy or outside of our range of experience. Instead, the revenge achieves a universality, a flaw of human character, or perhaps more aptly, a commonality of human emotion that Montressor works out for us that we, only in our unconscious, would dare to think about. Poe often treats such taboo subjects that he considers fundamental to human experience but too awful for a person to lay claim to. Indeed, in an essay on poetry he calls such horrific experiences and emotions "beautiful."