I've read The Shack by William Paul Young twice − once when it was first published and then before renting the newly released movie. I was grateful that the movie pretty much followed the book since one of my biggest pet peeves is when a movie doesn't.
The story offers a different approach to God's view of the world, one to which I know some Biblical scholars even subscribe in regard to God's "punishment." I will leave it at that. The movie did fail to include what I consider one of the most important aspects of the book which more or less proves the experience of the main character to be true. I'll leave it at that, too.
My biggest concern, however, wasn't the movie or its message. It was people's reaction to it as stated in their comments.
On one hand, you have a religious sect that takes exception with the way God is portrayed. He can't be black or a woman, and you must incur the wrath of God. Some of what these Christians cite to approbate their beliefs (not unsurprisingly) is from the Old Testament. I won't speak any judgment on that, but I prefer and believe in the loving God whom Jesus introduced us to in the New Testament.
Now, on the other hand, you have the atheists. I honestly don't know why they even bothered to see the movie, and maybe they actually didn't. There was a good deal of profanity. disdain, and outright loathing for Christians in some of their comments. I think this disturbed me more than the presumed fundamentalists who truly think they speak God's word.
I wondered what in someone's life would cause them to so vehemently deny that there is something greater than themselves. You can explain how things happened to create this world, but where did it begin? Substance had to come from somewhere.
In the end, it wasn't the difference in what I believe versus their non-belief that disturbed me. I simply felt sad for them. I also felt sad for the world because these are not the people who make our world a better place. Hate of any kind, from any group, never makes a positive difference for mankind.
I've known some very good, caring and kind people who were atheist or agnostic so the people who made these disparaging comments carried something different with them. The "great sadness" in The Shack refers to a specific matter, but I think there is another sadness that needs our prayers.