Richard Olin's "All Day Wednesday" (short story, hallucinations, free): What if the world stopped changing?
Story summary."All his life there had been too many bright guys with too many bright ideas. And the bright ideas got put into practice and then things changed. They could never leave a guy alone and just let him do his job. They always had to throw in the unexpected."
Here the fantasy of a static world comes literally true - an entire world of hallucinating people, stuck mentally in the daily routine they did on a certain Wednesday!
Fact sheet.First published: Analog, March 1963.
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Among the stories edited by John Campbell for Astounding/Analog.