Author: C.S. Lewis
A dream -- the people of hell climb aboard a bus destined for the valley of the shadow of life. It is the land on the fringes of heaven. All who want to stay in heaven can. The solid people of heaven come down from the mountains to invite them in. The shock of the book, is that none want to stay. The fringes of heaven is a damnable place, heaven itself must be even worse. Make no mistake the inhabitants of hell are miserable & getting more so every day, but they cling to their misery.
All inhabitants of hell are self absorbed. They are the centre of their own ever shrinking, ever disappearing, ever solitary universe -- but they want themselves, more than joy itself. When confronted, they lash out, blaming others for the fix they are in. Some are interested in God, but only as a means to an end. God is useful to better their own kingdom of self, or to get what they truly love. For others heaven is seen as a place to become a shining star. In every case, when the people of hell realize that they can't get what they want out of God and heaven, they become disgusted with it.
Disgust for the heavenly grows even more when the ghosts of hell (for in the story the people of hell become harder and harder to see) realize the earthly failings of some of the heavenly people. By comparison, the ghosts believe they are better. Some inhabitants of hell while on earth became so interested in proving the existence of God, that they come to care nothing for God himself. Others become so occupied with spreading Christianity that they never give a thought to Christ.
Even in these noble pursuits the means became the end. What they were doing was far more important than who they were supposedly doing it for. Regardless of the pursuit, noble or otherwise, when doing, performing, image, and self exaltation becomes the driving force of one's life, heaven actually becomes inhospitable, and undesirable.
Lewis' ability to capture the true darkness of a human heart is quite unsettling. The hell in all of us is revealed with convicting accuracy. The foolish choices we make in order to hang on to ourselves, at the expense of true joy, hit really close to home for the reader.