Wendy Torrance: Stay away from me.
Jack Torrance: Why?
Wendy Torrance: I just wanna go back to my room.
Jack Torrance: Why?
Wendy Torrance: Well, I'm very confused and I just need time to think things over.
Jack Torrance: You've had your whole fucking life to think things over.
What good's a few minutes more gonna do you now?
Dick Halloran: They turned out to be completely unreliable assholes.
Jack Torrance: Little pigs. Little pigs. Let me come in. Now by the hair on your chinny chinny chin? Then, I'll huff, and I'll puff, and I'll blow your house in!
Jack Torrance: Here's Johnny!
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?