Just thinking about The Thursday Murder Club again. The books are cozy mysteries, but they're also about what it means to age, how to build community, etc. they're really very good. They don't play the fact that the characters are old for laughs, and don't make them plucky and cutesy.
Elizabeth is actually pretty terrifying. Joyce is really hilarious. Ibrahim is pretty sad about some things, and Ron still has fire without a place to direct it. None of that really came through in the movie.
Also there are some very important characters that got short shrift. I like the movie less the further I've gotten from it, but a new book comes out next week so that'll be good.