Looking för en kort historia om en medeltida stad där önskemål beviljades oavsiktligt

En vän pekade mig bara här när jag frågade detta på Facebook. Jag har inte haft någon tur där, så förhoppningsvis kan ett mer engagerat forum hjälpa till att spåra det. :)

This has been bugging me for about 20 years now. I remember in 8th grade, one time the teacher handed out scrap paper and the back of my sheet had the first page of a short story on it that I still remember. The basic premise was that there was some nebulous, potentially malevolent force living under/near a medieval or fantasy type village that would make wishes come true whether the wisher wanted it to be true or not. To the point, the first paragraph mentioned that nobody there wished anyone else "good morning", but rather just said "morning" in passing, because wishing someone a good morning would make it good at the expense of someone else.

I don't know if there was then payment expected to the force, or it if exacted payment, or if the double-edged fulfillment of the wish was enough of a cost. It sort of read like a "Lottery" type vibe... dystopian, social costs, etc.

So... anyone have any ideas? I don't even know how I'd try to look it up. To this day I usually say "morning" in passing instead of "good morning" to strangers, and it always reminds me of this story. I'd love to at least read the whole thing and know what it was about.