Since I don't know the specific 'fear thy neighbor mailbox madness real story', it might be a story where the mailbox was somehow involved in a series of pranks between neighbors that got out of hand. For example, one neighbor might have filled the other's mailbox with unwanted items, like junk mail from all over the place. This could have led to a cycle of retaliation and more and more extreme actions, causing a lot of tension in the neighborhood.
Sorry, I don't have the exact details of this story. It could be that the mailbox was used as a way to send threatening messages between neighbors, which would be really crazy.
I'm afraid I can't provide the specific details of this story as I'm not familiar with it. However, it could be a case where the mailbox was at the center of a neighborhood mystery. Maybe the mail was disappearing regularly and one neighbor suspected another. This led to a full - blown investigation within the neighborhood, with people spying on each other, setting up cameras near the mailbox, and all kinds of wild speculation. There could have been false accusations flying around, which made the situation even more chaotic and turned it into a real 'madness' situation.