One thing that’s fun in reading older books or watching older movies is seeing little patterns of thought that are different from today. Not things like ‘these medieval characters think like medieval people’, but ‘these spacemen from the future do things I’d consider really unusual and it’s not part of being a spaceman’ or ‘this medieval person seems to have a distinct 60’s mindset’. I’m specifically excluding things like racial and gender issues here, and I’m not thinking of the blatantly obvious, like ‘they didn’t have cellphones in this 1940s movie’.
One example from EE Doc Smith’s Lensman books:
There’s a scene where the main character Kim is in deep cover to infiltrate a criminal operation. He goes off on a day trip to have lunch and fish while making a drop for the criminals. As part of his day trip, he brings a packaged lunch in box, then when he’s done eating collects the trash into the box and drops it into the late. While he will comment when he does things that are out of character to maintain cover, dropping trash into the nice lake you’re fishing doesn’t even warrant a mention, it’s treated as the perfectly normal thing to do. I don’t think you’d have a squeaky-clean hero today who casually pitches his lunch containers into a lake without a second thought, but back then it was just what you did with trash.