WRT "The Princess Bride", I've read it a few times as well. My perspective is slightly different, reading it after watching the movie many times. I agree that it "has its own sort of whimsy", especially in the context or meta-story, but when I first read it, I was struck by how similar the humor is to the movie.
If memory serves me, almost all of the memorable lines and jokes from the movie come word-for-word from the book. I'd assumed some of the jokes, e.g., those by Miracle Max (Billy Crystal) or Fezzik (Andre the Giant), were adapted to suit the actors. But they weren't. I don't know if that speaks to the quality of the writing or the casting or what.
If memory serves me, almost all of the memorable lines and jokes from the movie come word-for-word from the book. I'd assumed some of the jokes, e.g., those by Miracle Max (Billy Crystal) or Fezzik (Andre the Giant), were adapted to suit the actors. But they weren't. I don't know if that speaks to the quality of the writing or the casting or what.