Anybody who has read Stephen King books....
and I mean more than one; knows that all of his stories are about good vs evil. Plain and simple. Sometimes, like in Desperation, it is more about God as Christians see him. But in the Shawshank Redemption it was man vs himself, same thing with the Green Mile. In Firestarter it was the evil govt vs nature. In delores Claiborne, it was Delores vs her husband and then everyone else as time went on. And sometimes the battle goes on thru several novels(if you have read The Dark Tower series or the Talisman, The Stand and Needful Things) the evil is the Walkin Dude, Leland Gaunt or Randall Flagg; who I have deduced over time are the same person, just reinvented.
If you have really read his books, this is very obvious. And makes for great reading and sometimes great movies. The books are very conversational with alot of descriptions and characters talking to themselves. I am sure that is very hard to translate and condense into film format.