Not that I hate the show, I love it, but things are mixed up a lot with things that happened that didn't happen at all in the book and things in the book that the show completly mixed up. Why do the producers do that? Why not like the book?

The producers have said that they use the books as a rough guideline but don't feel bound to translate the books word for word. They emphasized that certain elements that work well in books might not translate to TV well, and vice versa. If anything, they use the books for inspiration but feel free to be creative within the larger framework of the story.