I think the other answers have hinted at this pretty well. It's not that people think the movies are so good, so much as they think the books are so good. Obsession over the books carries over into hype for the movies. read more
Many times a movie is "based on" a book, but has notable differences. In the case of the Harry Potter movies and even the theme park, they have executed the typically impossible feat of making a proper and exact adaptation. Regurgitating the lines from a text isn't difficult if you've built a quality cast. read more
Through a child’s eyes, obviously the Potions master seemed like a little bit of a downer, and Harry, Ron and Hermione immediately assumed he was in line with Voldemort, trying to steal an elixir of life, and even curse Harry off his broom. read more