* Obsessive focus on the old man's eye: The narrator becomes fixated on the old man's "vulture eye," which he claims drives him mad. This obsessive focus is a sign of his suppressed anger and resentment towards the old man, who he perceives as a threat.
* Extreme paranoia and suspicion: The narrator is constantly on edge, convinced that the police are suspicious of him. This paranoia is a manifestation of his guilt and fear that his anger and actions will be exposed.
* The act of murder itself: The narrator's meticulous planning and execution of the murder are driven by a desire for control and dominance over the old man. The act itself is an expression of his suppressed anger, a way to assert power and silence the old man's "vulture eye."
* The increasing paranoia after the murder: Even after the body is disposed of, the narrator is unable to escape the feeling that the old man's eye is still watching him. This intense paranoia is a result of his guilt and the realization that his anger has not been extinguished, but rather intensified by the act of murder.
The narrator's anger is not outwardly expressed through physical violence or verbal outbursts, but rather through his unhinged behavior, obsessive thoughts, and meticulous planning of the murder. This makes his anger even more unsettling, as it is a silent, insidious force driving him towards a horrific act.