In the 70s I started reading the Perry Mason novels -- and others by E.S. Gardner. Many of them took place in the 30's and 40's and even then I was jarred by some of the expressions and attitudes by characters in the book. But they (mostly) weren't central to the story and were windows into a different time. Some I didn't understand until much later -- characters would ask "Do you have car fare?" and I had no idea what that meant until much later when I learned about LA's old street car system (called "Red Cars").
Sort of the flip side of this, I've recently re-read some SciFi that was written in 50s and 60's that take place in the 2010's (ie "now"). It is fascinating how far off things are -- both in turns of what hasn't happened (growing up, I was always looking forward to taking a vacation on the moon
) but what they missed totally (mostly advances in computing).
You get some of the same things in older movies. I recently watched "White Christmas" (Bing Crosby/Fred Astaire) for the first time in a long while and the portrayal of African Americans was downright embarrassing.