I watched Back To The Future again yesterday and it suddenly struck me - the present day bits at the start and end are set on 25/26 October, but there are no Halloween decorations anywhere in Hill Valley.
Was Halloween not a big thing in California in 1985? Or do they not put decorations up 5/6 days in advance? Even in shops?
Of course the real reason is probably just that it was filmed in spring or summer and as Halloween wasn’t at all relevant to the plot it never occurred to the filmmakers that in reality at that time of year there should be Halloween decorations in at least a few places.
This is now bothering me far more than it should!!!