"The Shining" has always been for me a horror masterpiece and a Stanley Kubrick classic. Now, I've seen the film several times and I noticed clues in the movies that are not mistakes.
Clue 1: Remember the scene when Jack is writing and Wendy comes in to interrupt him? Well, he uses some profanity and throws away the paper he was writing. She turns and walks away. But then, he begins writing again as if he had never thrown away the paper. The haunted hotel is feeding Jack paper.
Clue 2: Many people have had questions about exactly what Jack's relationship was with the haunted hotel. Remember the scene when Jack is in the bathroom talking with Mr. Grady? Mr. Grady is right in front of the mirror and Jack is facing the mirror's direction. So, Jack is really Mr. Grady because he is really looking at himself.
Clue 3: There is actually a foreshadowing in the film. Remember the scene when Jack is in the car with his son and wife on their way to the hotel? Jack starts talking about cannibalism and the mother starts to worry about Jack talking about that around their son. But the son tells his mother not to worry because he knows all about that because he saw it on television. But later on Jack utters the classic line "Here's Johnny". But don't worry, he saw it on television!
No, these are not mistakes. They are clues into the mystery of "The Shining".