As a demon, Dean's soul became twisted and he no longer empathized with others. He cared only for himself and what he needed. His change was so drastic that he stalked Sam throughout the Bunker with the intent of killing him using a hammer, only to miss by a few inches. He carried out this task calmly, and coupled it with taunts, giving the impression that he was enjoying himself. This is furthered by the fact that instead of an axe, he decides to use a hammer to break through a door and kill Sam, despite both tasks requiring much more force with a hammer than with an axe. Demon!Dean apparently cared about the natural order , something old Dean despised. He even considered himself, as a demon, a part of the natural order, and that it was all set up in this certain way.