Anger. That had always been Jack's downfall. In life, he was shunned because of it.
But at least Carson cared. They were two very different men, but they had common ground in the fact that nobody really liked them.
And it made the monster smile, something which he hadn't done for years before they'd met.
Carson found the emotion grotesque, but learned to live with it each time.
It was a love-hate friendship, but they wouldn't have it another way.