1. The Dementors in Harry potter are based on author j.k Rowling struggle with depression after her Mother's death.
2. Even J.K Rowling didn't know what was Dumbledore wand was made of. And none of the fans ever asked.
3. J.K rowling did a accept that Hermoine and Harry pairing might have worked.( But honestly I really like Ron ☺️)
4. Our beloved headmaster Mr. Dumbledore was gay.
5. Harry Potter makeup artist applied Harry's lightening bolt scar thousands of times over the course of eight film.
6. J.k Rowling jotted down the Hogwarts house names on an airplane vomit bag. They were Slytherin, Gryffindor, hufflepuff, ravenclaw.
7. The magical plants taught in the Hogwarts school actually existed in Muggle world , aka the real world.
8. The actress who played the Moaning Mrytle in Harry Potter was older than the students (p.s I thought it was played by Daniel Radcliffe himself lol)
9. One of the creepiest villain in the history was Dolores umbridge, deemed by the famous author Stephen King.
10. Harry Potter production apart from the exceptional CGI also had an animal.
11. Everyone one of us wondered what happened to Dolores umbridge after she was taken to forbidden forest, well she was taken to Azkaban and imprisoned by Ministry of Magic.
12. Whenever Harry, Ron and Hermione were doing their Hogwarts homework, they actually were doing there real homework.
13. Hagrid played by Robbie Coltrane was the first actors to be cast.
14. In Harry potter The order of phoenix, Arthur weasley was originally was supposed to die but his death was replaced by Sirius Black.
15. Both Radcliffe and Grint admitted to having crush on Emma watson.

Harry Potter has been such a phenomenonal movies and such a part of life. I have watched literally every movie a multiple times. 

Which one is is my favourite? I would say third movie Harry Potter and the prisoner of Azkaban . They were young , a lot of magic included by the willow tree, the flying car and time pendant with Hermione. And a lot of Hogwarts to watch. And ya a little bit of chemistry between Ron and Hermione. 

The last two movies were a lot of dark and with all grown ups and obviously trying to a give a finish story to everyone.

And yes the first three movies I watch over an over again. 

Do let me know in the comment section which one is your favourite weird fact.