An example of Man vs. Man is the narrator killing the old man. The old man ends up dying resulting with police officers coming over and investigating in his house.
Man vs. Self
AHHHH! WHY CAN'T THESE OFFICERS LEAVE?! ALMIGHTY GOD NO! THEY MUST'VE SUSPECTED ME! ARE THEY'RE MAKING FUN OF ME?
Here, the narrator is disposing of the old man's blood in the tub. Then, he places the cut-up dead body under the floor, everything already clean. This is an example of Man vs. Nature because the narrator is fighting against a mental illness he does not know of. His unknown insanity affects him during an encounter with the officers.
But why will you say that I am mad? The disease has sharpened my senses-not destroyed- not dulled them.
This displays the narrator vs. society ( the police officers ). The narrator lies about the dead body, feeling guilt building up inside his body. As a result, he goes crazy in front of the officers.
This panel shows man vs. self where the narrator feels guilty about not telling the officers that the old man's heart is under the plank. He goes into a mental breakdown, confessing his wrongdoings to the officers.
For this example, the narrator claims that he is not insane. However, as the story progresses, the readers know the acts the narrator has committed are driven by his insanity. Insanity drove him to kill the old man, leading to multiple conflicts in the plot.
How then, am I mad? Hearken! and observe how healthily-how calmly can I tell you the whole story.