Harry Potter is a series that you have to live under a rock to not know about. While the books are extremely good and some of my favorite pieces of literature, the movie adaptations are definitely not groundbreaking. They do not follow the books exactly, and while it is understandable that they can not fit every single event into the movie format, there are some things they change and miss that make no sense.
There is a spoiler in the next part, so proceed with caution.
In the movies, Neville gives Harry the gillyweed so he can breathe underwater and complete the second task in the Triwizard Tournament. In the books though, Dobby is the one to give Harry the gillyweed. Another thing that annoys me about the movies is that some of the characters do not look like how they are supposed to look. Voldemort is supposed to have red eyes, but in the movie he has no red eyes. Snape is also way less mean in the films than he is in the books. One more thing is that the longest book, Order of the Phoenix, has the shortest movie adaptation. They don’t even have enough time to show everything that happens, and there’s a lot of montages. It’s very annoying.