Harry Potter and the Order of the Phoenix, the fifth film in the series, chronicles Harry's life at Hogwarts as he deals with witnessing Cedric Diggory's death and Voldemort's return while the Ministry of Magic feigns ignorance of both. On top of that, The Daily Prophet slanders him and Dumbledore on the orders of the Ministry, and the new Defense Against the Dark Arts professor psychologically and physically abuses students.
The film is overall pretty solid with quality cinematography and acting. The storytelling and character development are also good, but there are still some holes in both. Because of the holes, there are some parts of the film that just don't make sense. Here is a list of ten of them.
10 Hermione Agreeing To Do Ron's Homework
Hermione is known for valuing education and rules. Later in the film, we see her develop an affinity for breaking the rules when she helps found Dumbledore's Army. She also has helped both Harry and Ron with their homework in the past. However, she is notoriously strict about cheating, and theoretically would not outright do homework for either of them.
Early in the film, before she finds pleasure in rule-breaking, Ron asks her to write a paper for him. At first, she refuses, but he is able to convince her to write the introduction for him, contradicting her earlier views on education.
9 Voldemort Making An Appearance At The Ministry
During the final battle of the film, Voldemort makes an appearance to personally face Harry Potter himself. He also battles Dumbledore, with whom he is evenly matched.
It kind of makes sense that he makes an appearance, as he probably was looking to kill Harry and get away before anyone in the Ministry arrived, which he confidently thinks will be the outcome. However, in the film, he spends a year in hiding and being cautious, only to appear in the main lobby of the Ministry, where he can easily be caught if he isn't careful. He is not careful and lets his confidence get to him, and he is consequently seen by Cornelius Fudge and other Ministry personnel.
8 The Meeting At The Hog's Head
Hermione sets up the recruitment meeting of what will be called Dumbledore's Army at the Hog's Head, an inn and pub in Hogsmeade. It is a quiet location for a meeting, unlike the loud, hustle and bustle of the Three Broomsticks. Hermione's reasoning is that the quiet would be better for the meeting, but the quiet pub ended up being the reason why they were caught in the books.
Narratively, they needed to be caught to add conflict to the story, but had they met at the Three Broomsticks, a large group of students would have appeared less suspicious. The group got caught in the film because Umbridge has eyes and ears throughout the school, and they discuss their meeting loudly, meaning that in the film, they could have had the meeting anywhere besides the Hog's Head.
7 Using Muggle Money To Operate The Ministry Visitor's Entrance
Arthur Weasley escorts Harry to his hearing at the Ministry. As they enter the Ministry, Arthur comments about taking the visitors' entrance, located inside a red telephone booth, and using muggle money in order to operate it.
The use of muggle money to operate a magical telephone booth does not make sense because a muggle could happen upon the telephone booth and try to use it. Some magical objects, including houses, are hidden from the muggle eye, but it is never explained if the booth is hidden or somehow proofed to avoid muggles accidentally entering the Ministry.
6 No After-Hours Security
Aside from Arthur being shown patrolling the Department of Mysteries before getting attacked by Nagini, there seems to be no security depicted as patrolling the corridors after hours in the Ministry. Furthermore, it is unclear if Arthur was patrolling the department under orders of the Ministry or the Order of the Phoenix.
Because there is apparently no after-hours security, a group of underage students, Death Eaters, an alleged ex-convict, other Order members, Voldemort himself, and Dumbledore, who was in hiding, are all able to enter the Ministry with ease.
5 Sirius Taking His Human Form At King's Cross
It makes sense that Sirius, an animagus, would want to see his godson off to school, which he mostly does so in his dog form. However, he pulls Harry aside into a private room where he reverts back to his human form so that they can talk.
This moment in the book is used as a "close call," in which Sirius was almost caught by the Malfoys. No such instance occurs in the film, making the scene unnecessary. Sirius could have easily pulled Harry aside at Grimmauld Place, as he has before, in order to avoid potentially blowing his cover.
4 Using Thestrals Instead Of Brooms
After Harry and his friends escape from Umbridge and her Inquisitorial Squad's clutches, they start devising a plan to rescue Sirius, who they believe is held captive by Voldemort in the Department of Mysteries. Luna suggests using Thestrals which they ride all the way to the Ministry.
Thestrals don't make sense because only Luna and Harry can see them, and they also could have used brooms. If they were worried about being discreet, discreetness and flying brooms were a nonissue earlier in the film when Mad-Eye Moody, Tonks, and Kingsley Shacklebolt picked up Harry to take him to Grimmauld Place.
3 Breaking Into The Room Of Requirement
During the time in which Dumbledore's Army was meeting, Filch and the Inquisitorial Squad attempted several times to infiltrate the Room of Requirement, where Dumbledore's Army met. At one point they almost successfully got in, but the Room of Requirement turned into a broom closet for them at the last second, keeping Dumbledore's Army safe for another day.
Later, Umbridge was able to break the wall of the Room of Requirement and enter into the same room. The fact that the room didn't change itself for the outsiders this time feels more convenient for the plot than anything else.
2 Ron And Hermione's Silence Over The Summer
Dumbledore did instruct Ron and Hermione not to tell Harry about the Order of the Phoenix, probably for fear of infiltration from the Ministry or Voldemort. However, Ron and Hermione could have still written to Harry and told him about their summers outside of the Order. If Harry raised questions about the content of their letters, and it had something to do with the Order, they could have explained to him that they would have to tell him about it in person.
Some kind of letter, even just checking in on Harry's summer, would have helped Harry immensely considering he was still dealing with Cedric's death. (Of course, as with many things, this is explained in the books - where Ron and Hermione do write, just without any real useful news for Harry.)
1 Cornelius Fudge's Paranoia
As it is mentioned in the books, a lot of people wanted Dumbledore to be the Minister of Magic, but he constantly turned down the offers. Cornelius Fudge was likely aware of the offers and should have been aware that Dumbledore was content at Hogwarts. However, Fudge immediately jumped to the conclusion that Dumbledore was claiming Voldemort was back in order to steal Fudge's job.
Dumbledore stuck to his story the entire time Fudge didn't believe Voldemort was back. If Dumbledore were lying, he likely would have changed the story. Also, the fact that Voldemort's return does not mean Fudge automatically needs to step down. He did step down, but only because he perpetuated lies to the public.