Biggest plot holes in Harry Potter. (all books)

[Dávid]

Please tell me your biggest plot hole finds in Harry Potter because it's rather amusing how J.K. forgot so many little details in the story.

[Emma]

I was always wondering how Harry wasn't able to see thestrals before book 5 since he saw Quirrel and Lily die.

[Kristina]

Emma wrote: "I was always wondering how Harry wasn't able to see thestrals before book 5 since he saw Quirrel and Lily die."

I think he was unconscious when Quirrel died so then he wouldn't have seen death, as for his mother, I don't know, maybe there is something about being at such an innocent age that you don't remember the death.

I do have a Thestral plot hole though, at the end of book 5, after Cedric, the last chapters include them going to the train via the "horseless carriages". I think it is even mentioned in the chapter that he sees the carriages as being pulled by nothing. It isn't until the beginning of the 6th book that he sees the Thestrals.