These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Also the quiet exchange between Miss Pettigrew and Joe, the oldest characters in the movie who lived through World War I, when the "young set" are pointing excitedly at the planes flying overhead:
Guinevere: They don't remember the last one, do they.
Joe: No. They don't.
Also when Miss Pettigrew tenderly asks Joe Blomfield, as he's reading the newspaper article about Hitler's invasions, if he "knew people" (who had been rounded up by the Nazis).
Guinevere and Delysia only knew each other for one day before Delysia and Michael left for New York.
Values Dissonance: 70 years passed between the writing of the book and the making of the movie. Consequently, when the movie came about, some of the sentiments expressed in the book (particularly about Jews and foreigners) had disappeared. It's not hard to see why. There remains some Deliberate Values Dissonance, mainly in that attitudes of the sexes about appropriate touching and honesty between genders.