As detailed and engaging as Wizarding World is, the J.K. Rowling's fictional universe isn't perfect, and there are some parts that straight up do not make any sense whatsoever. While the stories that she told were great fun, the world-building is often considered one of the weaker points of the Harry Potter franchise, with Rowling often making significant changes to the story through tweeting as well as leaving large plot holes that, if looked at for too long, completely change how we understand how Harry's world works. This list of things that just don't seem to make sense in the Wizarding World are bound to leave even the most dedicated Potterheads scratching their heads.
Immoral Spells and Potions Are Legal
Love potions are similar to the Imperius curse in that they both manipulate their targets into doing the caster's will. Certain spells such as Obliviate are also highly morally questionable as they can wipe someone's memory, including crimes and traumatic experiences committed by the caster. Both of these should easily be up there legally with the Unforgivable Curses, yet anyone can cast Obliviate, and love potions can be easily purchased at joke shops.
Wizard Healthcare
The magic healing that we get to see in the films is often nothing short of miraculous, including growing entire bones from scratch after they've disappeared. This raises the following question: what other magical solutions are there to other health issues? If they can grow bones back from nothing, surely they could fix Harry's vision or give Mad-Eye his real eye back, or are vision-related problems not covered under Wizard healthcare? As well, it seems like no one has ever heard of the dentist, judging by the confused looks that Hermione got when she told the Slug Club of her parent's occupations, yet the "dentist" was an option on the Weasley family's movement-tracking clock in The Chamber Of Secrets.
The Rules of Quidditch
In the wizard sport of Quidditch, the chasers score 10 points for every goal that they make with the quaffle, while the seeker who catches the Golden Snitch can earn 150 points for their team. This effectively makes the Snitch the game-decider, as it would take nothing short of a huge imbalance on the skill level of the chasers to make up for all of those bonus points earned. The game would make a whole lot more sense and the points would actually matter if it wasn't for the Snitch.
The game is also ridiculously dangerous and is essentially pay-to-win, giving privileged students like Draco Malfoy a significant advantage on the field. Students who can afford the high costs can purchase their own advanced broomsticks, and broom makers will keep finding a way to make brooms increasingly faster. Harry pretty much received the broomstick equivalent of a Ferrari when he was gifted the Firebolt by Sirius.
Muggle Technology
While much of the magic utilized in the Wizarding World appears to be superior to things in the muggle world, there are in fact many technologies that muggles use that give them an edge over their wizard counterparts. If wizards need to get in contact with someone far away, they would have to send a letter via owl, whereas muggles can use phones or fax machines to instantly get their message across. It is known that most of the Wizarding World is ignorant about muggle life, which is surprising considering they also have a number of muggle-born within their ranks. Perhaps this is just an excuse to have the stories be set in modern times without having to worry about using modern technologies.
Wizard Transportation
With the existence of portkeys, apparation and Floo powder in the Wizarding World, why do wizards even need any other means of transportation like trains, buses or flying cars? While the books did explain that portkeys had to be authorized by the Ministry, they can also be reused indefinitely. The Ministry could set up portkeys or designated spaces for wizards to use Floo powder and apparate, allowing people to get to where they need to go instantaneously.
The Triwizard Tournament
Outside of the first task, the entire tournament must have been boring for the spectators as well, since they wouldn't be able to make out any of the excitement. Most of their time is spent waiting for something to happen after the champions disappear into the maze or the lake. The students must have just been happy to be excused from class. The problem with the Triwizard tournament doesn't stop there, however.
Could Harry have just not participated in the tournament? It's clearly against the rules for someone of Harry's age to participate, and after three attempts on his life in the past few years, surely someone must have known that it's a trap. They handwave this by explaining that it's part of a contract, but Harry never consented to the contract as he never put his own name into the Goblet. Would the Ministry have taken him to court if he refused to take part in the competition?
Why Did Voldemort Need Harry to Be in the Triwizard Tournament?
Voldemort's plan to use Harry's blood to bring him back to his full form relied on the off-chance that not only would Harry would be the first to reach the Cup, but the Ministry would allow someone not of age to participate in the Triwizard Tournament, something that has never happened before in its history. Instead of going through a whole book's worth of trouble, a much easier way would have been for one of Voldemort's followers, maybe Barty Crouch Jr. while disguised as Mad-Eye Moody, to do the Wizarding World's equivalent of phishing and send him a letter containing a portkey. One thing's for sure: the Death Eaters went through a lot of unneeded effort to bring Harry to the graveyard.
Time Turners Break the Entire Plot
While the Time Turner cannot be used to change past events, just think about how many plot points could have been solved through its use. The device allows its user to go back up to a limited amount of time and observe events in the past without affecting the present, meaning some significant plot points from the books, including finding out who opened the Chamber of Secrets as well as the identity of the person who put Harry's name in the Goblet of Fire, could have been easily resolved. Rather than being put to better use, the time turner was instead given to a student so that they could enroll in more courses.
Fred and George Knew About Peter Pettigrew
The Marauder's Map, first introduced in The Prisoner of Azkaban, was a magical document acquired by Fred and George Weasley that revealed not only every hidden nook and cranny at Hogwarts but also the name and location of everyone at the wizarding school. Hence, the surprise reveal that Ron's pet rat Scabbers was actually Peter Pettigrew should have been known to the Weasley twins.
Even if they did not know who Pettigrew was, surely they would have seen that their brother was sleeping with some strange man every night. The series tries to bypass this plot hole by having the twins claim they haven't used the map in a long time, implying that they haven't used it since Harry and Ron arrived at Hogwarts. This still doesn't explain things, however, as Scabbers previously belonged to their older brother, Percy.
Hogwarts Is a Terrible School
Between the moving staircases, three-headed dogs and a killer tree, Hogwarts is a dangerous place for students even before factoring in the annual assassination attempts on Harry and his friends. The professors (and even the Headmaster) shows clear favoritism and have a history of hiring incompetent teachers, with some even turning out to be murderers in disguise. Hogwarts may be a magical place, but as an educational institution, it's a mess hardly worthy of being considered one of the finest wizarding schools as the films and books implied.