I felt the same way. I was reading it when the movie first came out (so it's been a while) and wanted to finish the book before seeing the film but when I finished the book I was so done with the story I almost didn't go only to find that the movie, while not great, was entertaining.

The actors and more concise storytelling greatly improved the story. All while reading the book I just felt like it was just going through the motions to hit certain story beats.