I see what you mean, I dont read books at all so ive never been disappointed by a book made into a movie (unless the movie was just bad anyway), seems what you are talking about is happening a lot these days, just from what other people are saying.
Stephen King recently made an interesting point about that sort of thing though, he pointed out that books and movies are two entirely different mediums, and shouldnt be compared to one another.
I think his exact words were something like this: "the movie didnt change the book, the book is still there, on the bookshelf, for you to read and enjoy at any time".
From someone who doesn't read, i thought it was interesting qoute 
Stephen King's book Under The Dome was recently made into a TV show and got a lot of criticism, thats he was talking about it.