My story is implausible because elderly people can't hear? That's certainly a take, given how the "angry old lady downstairs knocking on the roof with a broom" is a super common trope. This woman was in her 60s, they can generally hear just fine lol. If you literally believe people would never complain unless there was genuinely something to complain about, then you have been extremely privileged in your selection of neighbors. There are tons of unreasonable and shitty people out there. There are also people who have aforementioned hypersensitivity or other mental issues. These things cause people to disagree on what characterizes a normal level of noise. Negotiating this shit is part of what it means to live in close proximity to each other, and it's way harder in an atomized society where most people in the city don't know their neighbors.

I saw the letters she would dump in their mailbox, and they didn't look like the work of a healthy individual. I also happen to know that my sister and her husband was (and still are) very chill people who don't party, listen to loud music or have screaming matches which also wasn't what she complained about - it was literally things like "talking loudly" and "moving furniture" (half the time the complaints and "logs" were dated to times when they were both in bed). They noped the fuck out of there because there was no reasoning with this person, and they wanted to start a family. I can only imagine what would have happened if there was an infant in the mix too. Which is, incidentally, another source of noise that you sometimes have to put up with when you live in an apartment (my own downstairs neighbor had a baby with colic. It sucked, but that's life).

Like, I get that nothing is ever true on the internet etc. but for real, what the hell is implausible about this story?