Trivia: Stanley Kubrick was very protective of Danny Lloyd, because he was so young. Through some careful and clever directing, Lloyd was unaware he was making a horror film until after the film's release.
Trivia: Kubrick tortured Shelly Duvall to get the performance he wanted out of her. He told the crew to have no sympathy for her, and pushed her to do many retakes until she would cry. The scene where she walked backwards on the stairs with the baseball bat was filmed up to 127 times by some counts. At the end of filming she presented Kubrick with clumps of her hair that had fallen out due to stress.
Trivia: The line "Here's Johnny" originated on the The Tonight Show with Johnny Carson, where Ed McMahon always introduced him with that phrase. Nicholson improvised the line during the shooting; Kubrick liked it and left it in.
Trivia: Initially, the bathroom door Jack Nicholson was to axe in was an extremely thin one, made by the prop department to make it easier to destroy. However, Nicholson's technique with the axe was so good (he'd been a volunteer fire marshal) the door shattered into a million pieces, so they had to build a much stronger door to handle his swing.
Trivia: The famous scene where Wendy reads through Jack's accumulated work naturally doesn't have the same impact if the viewer can't read English. Therefore, for every foreign language the film was released in, Kubrick remade this shot with an appropriate cliche in each language - French, German, etc. Also, every page of every manuscript was hand-typed to recreate the realism of typos and misalignments.
Trivia: Stephen King attempted to persuade Kubrick not to cast Jack Nicholson as Jack Torrance. King believed that either Michael Moriarty or Jon Voight could have played Jack's descent into madness more convincingly.
Trivia: According to the Guinness Book of World Records, The Shining holds the record for the film with most retakes of a single scene (with spoken dialogue) at 127 takes. The participant in those retakes was Shelley Duvall.
Trivia: Jack's limp at the end of the movie was a real injury sustained when Jack Nicholson got drunk and fell out of a hotel window the night before shooting this scene.
Trivia: The injured guest who frightens Wendy Torrance by saying "Great party, isn't it?" was played by film editor Norman Gay.
Trivia: An outtake from the opening sequence was used in the "happy ending" version of Blade Runner, but removed from the director's cut.
Trivia: For the famous scene where Jack Nicholson breaks down the door with an axe, the crew made a fake door for him to break through, but had to replace it with a real door as the fake one broke too quickly due to Jack Nicholson's prior training as a fireman. This dates to his period of military service in the Air National Guard in 1957. After completing basic training at Lackland Air Force Base, Nicholson performed weekend drills and two-week annual training as a fire fighter assigned to the unit based at Van Nuys Airport. Some sources state they went through 60 doors during filming to get the footage Kubrick wanted.
Trivia: The infamous "Here's Johnny!" scene took three days to film.
Answer: Effectively, Danny's shining is what brings the hotel to life. Because he has such an incredibly powerful shine about him, all these weird ghost things in the hotel are able to materialize and reveal themselves. These weird ghost things are always present to some degree, and those people with a small degree of shine get glimpses of them - like Dick Hallorann. (It's not quite made clear in the movie, but Dick saw the woman in room 237 in the book). However, Danny's shine is so great that he gives these forces enough life to appear to those without any shine, people like his father and mother. As it's the hotel that's slowly driving Jack crazy, and the hotel gets its power from Danny's shining, then I'd say there's definitely a connection between Jack's insanity and Danny's abilities. In the movie, it's not as clear as it is in the book, but Jack is effectively possessed by the hotel. He's not a flawed drunk with an anger problem who loses his mind because of isolation. He's a flawed drunk with an anger problem who's doing the best he can, until the forces of the hotel get inside his head and make him lose it.
If Danny's shining is what brings the hotel back to life, does this mean that all the previous "Jacks" had a son or daughter with the shining too?