(I recently sold a pool to an elderly customer. Right after the installers leave, she calls the store.)
Customer: "Hi, may I speak with [me]?"
Me: "This is [me], how may I help you?"
Customer: "I just had my pool installed today."
Me: "Oh yes, how did everything go? Are you satisfied with the job?"
Customer: "Yes everything is perfect, but I was wondering what box the water came in? I think the delivery men may have forgotten it."
The customer isn't acting entitled or abusive to the salesperson. She wasn't forgetting about something about the product that should be obvious, like holding a TV remote backwards. It wasn't ignorance of cultural stuff either, like being offended that she can't spend American money in Canada. (Both of those are other stories on the site.) She was forgetting about the basic facts of life (water doesn't come in boxes, which would be both ridiculously heavy and unnecessary if you have a hose). The woman, specifically described as elderly, is probably senile or close to it.
There are more like that. Sometimes the person is described as old, sometimes not, but a lot of stories that look like a mental problem or at least mental lapse rather than just something funny or stupid or asshole-ish someone did. It's impossible to be sure, of course, since most of these are probably not direct quotes, but one person's side of the story from memory. Still, as fun as Not Always Right is, there can be a bit of mood whiplash reading stories as they go from "wow, what an insane asshole" to "hah hah, what an idiot" to "oh wow, I hope that parent doesn't normally have custody". Or just "I feel guilty laughing at people with aphasia."