1. Peter Pettigrew showing up on the Marauders Map.
We find out in HP3 that Scabbers is in fact a human and that the Marauders map completely outed him because it doesn’t take into account their disguises. Harry has just had the map for a few days when he notices Peter Pettigrew scurrying around Hogwarts. So, how do experienced and witty pranksters Fred and George have the map for years and not notice that Scabbers seems a bit strange on the map? I mean, are they not the least concerned that some random stranger seems to be sleeping with their younger brother every night? Was the map glitching or something when Fred and George had it? Did they just simply not look close enough?
2. The layout of the Triwizard tournament.
We aren’t really introduced that much to the layout of how everything was in the books, but we definitely see in the movies. Which dumbass wizard decided it would be good enough for the spectators to be standing above the surface of the lake when much of the 2nd task takes place underwater? Or to have the spectators outside the maze in the 3rd task when you can’t even see through the walls? I don’t know about you, but I’d much rather be inside doing some well-earned revision, rather than standing outside on a platform for 2 hours above a freezing cold lake, with no clue what’s going on under the surface. Just saying.
Filch is a squib. By definition, a squib is someone of magical descent and parentage, but don’t show any sign of magic. Basically half wizard, half muggle. And yet Filch is employed as the caretaker of Hogwarts. This is what gets me. Why hire an incompetent non-magical person to clean up Hogwarts when you can just do it in a second with a swish of your wand? Why even have a caretaker at all? It seems to me that Hogwarts is just trying to be nice to the unemployed or to give characters a minor antagonist throughout the story.
4. The process of explaining to muggle-borns.
In Harry Potter, Hermione explains that muggle-borns are put through this special process to get into Hogwarts, where a wizard must go to their house and explain the situation to their muggle parents. I just find it hard to believe that their parents just let them go off to some completely out of the blue school they’ve never heard of before, only with the word of some stranger who appeared randomly at their house. Is there anybody out of the many muggle parents who don’t suspect that this is some sort of child trafficking scheme? If I were a parent, and some random stranger appeared suddenly telling me that there is a hidden magical world and their child is invited to a school to learn magic, I’d want to look further to make sure this wasn’t some sort of scam. Isn’t there an open day of some sort? If so, we’ve never seen any parents in Hogwarts in the books or the movies. The parents of the Harry Potter universe really don’t give one about their kids.
5. DADA teachers.
Why did Dumbledore appoint Gilderoy Lockhart when he himself and the other professors knew that he was incompetent and didn’t have enough brain cells to rub together? And why did Dumbledore appoint a werewolf to teach kids when there was an obvious safety issue right there? It seems to me that the Headmaster doesn’t care at all for his student’s safety and wellbeing. I know that it didn’t really matter in HP2 because they didn’t really need to learn much anyway, but what about the kids who were doing their OWLS or NEWTS that year? I’m pretty sure there is only one teacher for each subject in Hogwarts, right? This means the kids who are about to take a really important public exam which will probably decide their future have been landed with an idiotic selfish brat who only cares about teaching them about his books. Great job Dumbledore, that’s a whole year’s worth of students who can’t become Aurors now. And then for the issue of Lupin. I know, he got a wolfsbane potion to drink regularly, but shouldn’t the ministry have a say in who Dumbledore appoints? It must be a pretty stupid government if they’re letting a werewolf into a building full of kids. We are shown in HP6 that the post had been jinxed by Voldemort ever since he got denied the job. But I doubt that the jinx prevented Dumbledore from hiring good proper teachers.