In my opinion, the Harry Potter book series will always be the best of the best. I can't imagine the books fading from fame, because I just think it will be one of those book series that never dies and is just a classic. But if you read the books a lot and you're obsessed with the Harry Potter books and films as much as I am, you'll find some pretty cool stuff. Here they are:
1. Lily gave birth to Harry at age 20
This isn't very important, but Lily and James were married and gave birth to Harry when they were TWENTY. I don't know about you, but I think 20 is kind of young to have a child. I mean, it's basically saying that you're old enough to have a child, but you're not old enough to drink alcohol...legally.
2. The centaurs predicted the events of the Deathly Hallows
Now, this doesn't go by the movies as much as it goes by the books. At one point in Harry Potter and the Sorcerer's Stone (that's what we call it in America because apparently, people think Americans are too stupid to know what a philosopher is), Draco and Harry are serving detention in the Forbidden Forest when they run into Voldemort drinking the blood of a unicorn to become immortal, and he was drinking it for Voldemort. Then, Voldemort sees them. Draco escapes, but I guess Harry didn't know how to fire a spell at Voldemort or something, so Voldemort is about to kill Harry, but he is luckily saved by Firenze, a centaur.
In my opinion, that's too convenient.
You may tell me that Firenze was just walking by and saved Harry from getting killed by Voldemort. But centaurs read the stars, and later, Bane arrives and acts as if he knew this would happen all along. This means that Harry getting killed by Voldemort in the Forbidden Forest was in the stars. And in the final book, Harry walks into the Forbidden Forest, turns himself in, and there, Voldemort fires Avada Kedavra at him.
However, due to the Horcrux inside Harry, the Killing Curse just destroyed the Horcrux, and thus, Harry survived.
3. Malfoy's Eagle Owl
In the first book, it is mentioned that Draco would get a lot of care packages from his parents using an eagle owl he owned. But then, in Goblet of Fire, Harry is in the owlery, and he notices an eagle owl flying away from school. And later, in his dream, he's riding on the back of an eagle owl, taking a message to Voldemort. So that eagle owl he saw was almost definitely the Malfoys' owl, delivering messages from Barty Crouch Jr. to Voldemort. Wow.
4. Trelawney's prediction
We know that in Harry Potter and the Prisoner of Azkaban, Trelawney correctly predicts that the person that betrayed Harry's parents would return to his master that night. But there was another prediction that she made, but was extremely overlooked in that same book. She predicted that when 13 people dine together, the first to rise would be the first to die (she says this after Harry receives the Firebolt). Professor McGonagall believes this is preposterous, but this came true...twice.
In Order of the Phoenix, Sirius rises first at a dinner in Grimmauld Place. He dies months later in the Ministry of Magic. Then, in Deathly Hallows, after the battle of the seven Harry's, 13 people dine together and Remus Lupin rises first, and he is later the first to die in the Battle of Hogwarts.
5. The number of Hogwarts students don't add up
When Harry first goes to Hogwarts, there are approximately eight people that go into Gryffindor, and there should be around the same amount of people in each house. So, let's say that each year, 8-10 people enter each house, while the seventh years leave the school. There are four houses and you attend Hogwarts for seven years. We do a little math, and that means that in total, the amount of students that attend Hogwarts is between 224 and 280. But the writer of the books claims that there are about 1000 students in Hogwarts...
6. There are witches and wizards that went bad who weren't in Slytherin
It has been mentioned a few times in the books and the films that there's not a witch or wizard that went bad who wasn't in Slytherin.
When people think of Slytherin, they usually associate them with bad guys because Voldemort was in Slytherin, and so were a bunch of Death Eaters. However, there were Death Eaters and Voldemort supporters that didn't come from Slytherin: for example, Peter Pettigrew, aka Wormtail. He was a Gryffindor and he is the one that betrayed Harry's parents and is the reason Harry was depressed for ten years of his life. Also, Wormtail is the one that killed Cedric Diggory (IT WASN'T VOLDEMORT. VOLDEMORT TOLD WORMTAIL TO KILL HIM).
Also, Quirnus Quirrell. Quirrell had Voldemort with him the entire year during the first book. He was a Ravenclaw.
7. Dumbledore is kind of insane
In the first book, Dumbledore says that the Forbidden Forest is off-limits, as in COMPLETELY off-limits. But later in the book, Harry, Hermione, Neville, and Draco have detention in there. So, apparently, the Forbidden Forest, which is so dangerous and infested with werewolves and acromantulas (the giant spiders in Chamber of Secrets) that it's actually has "Forbidden" in the title, is off-limits, unless, of course, a few first years walk around the school at night. Then, OF COURSE, they can get eaten by werewolves and giant spiders. I mean, that's perfectly reasonable, isn't it?
Also, in Goblet of Fire, Dumbledore allows a 14-year old to participate in a deadly contest that involves getting burned to death by dragons, getting killed by mermaids, and a dangerous maze where according to Dumbledore, "you may very well lose yourselves."
Dumbledore, you crazy old man.
This isn't important, but in the Opening feast of the first book, Dumbledore has a few words for everyone and after that, all he yelled was, "Nitwit! Oddment! Blubber! Tweak!"