The Harry Potter films have become one of the most beloved film franchises of all time. They've grossed over $2 Billion at the box office and they've taken the Potter fandom to heights that the books never could have on their own. The films also put faces to names and shown the world what real magic looks like, but they are not without their flaws.
Most Potterheads agree that the films lack many of the details that make the books so entrancing. It's come to the point that the fandom itself has been split in two: those who have read the books and those who have only seen the movies. While a movie fan may know all there is to know about the Harry Potter film cannon, there's just so much that they don't know about what's really been happening at Hogwarts.
For fans who have read the books, the hopes of seeing some of their favorite moments on screen were crushed when the filmmakers left them on the cutting room floor. It's understandably difficult to fit an 800+ page book into a 2 hour slot, but some decisions are undeniably questionable. The fandom has been significantly upset about certain characters they couldn't see on screen, as well as certain plot lines that were deemed unnecessary.