In The Tell-Tale Heart, the narrator struggles with his own madness, fueled by the pale blue eye of the old man. Although he very clearly says many times at the beginning that he is in fact not crazy, I think it is fairly obvious that anyone who is driven to murder simply because their blood runs cold at the sight of an unusual eye is crazy to at least some extent. The old saying, "The lady doth protest too much" is very applicable to this narrator, who repeatedly says at the beginning of the story that he is not mad, and proceeds to describe his various actions as if they were something that a mad man was not capable of. While denying his insanity, the narrator claims that it is the eye itself that is his problem; that is why he decides to kill the old man. He says that he had no problem with the old man, but just his eye bothered the narrator so much that he needed to kill the old man.