It took him a long time to notice that he was beginning to let things slip, and it was a long slide towards a bitter humanity. It was the little things at first, which is why he hadn't noticed the sum of them. Lies that were not worth telling, but he uttered them anyway. It was more the things that he ignored, let slide right by him, because no orders came to tell him otherwise. If he had noticed, it could have felt like a return to how he had been before. For Millennia he had just watched the world and wondered at it; the diversity and the beauty. There was nothing too big or small to ignore. But now the detail was lost on him, forgotten as unimportant as he passed through the world. He used to see everything, right down to the molecules, but now he saw nothing of import, only the surfaces. Even the shining beauty of the human soul was beginning to fade from his perception, especially one soul in particular; Dean Winchester's. Once, when he had remade the unremarkable human around that scarred soul, Castiel had tended to every cell, feel every nuance of Dean's recreation. And once he was complete, he had felt that profound bond that he thought would never be broken. But as Dean and Sam's lives had become harsher, more dangerous; the hunter's life, it had become harder for the angel to see inside him, to see his soul glowing from within. Since Castiel had become human, bonded with his vessel, his abilities to sense anyone's soul had faded. And he missed it. Being human felt heavy, confining and slow. Sometimes he couldn't stand the weight and the wait of it. The feelings made him bitter and impotent sometimes, and it was a shock to discover that ordinary humans sometimes felt like that too, as though they had something better to compare it to, Perhaps they had remembered once being loved by God, the father of them all. The father who had abandoned him, and let him fall.