Sarcastic
James Frey is not your typical rehab patient. He doesn't take the counselors or the other patients seriously. He actively mocks the Twelve-Step program. And he's a jerk. (Seriously. We're being nice here.)
Take this example from Part 4, Chapter 2, near the very end of the book. At this point, James already knows he's about to leave rehab. His job is to be greeter, so he goes to talk to a new patient:
What do you want?
I'm the Greeter. I came to greet you.
Go greet someone else.
I laugh.
Go away.
I laugh again. (4.2.11-4.2.17)
Later, the man tells his story, and what do James the guys do? "We laugh at him and we laugh at his story. At first he is angry and confused by us and our laughing, he doesn't understand it […] Michael the Catholic comes to understand that we are not laughing at him, but with him" (4.2.32).
Except Michael isn't laughing. Yes, he begins to laugh, but maybe it's just to get the crazy laughing maniacs away from him. James constantly mocks other patients, their success stories, and their problems. By the time each patient leaves, he usually manages to say something nice to him, but the fact remains that James himself never changes. He is stubborn, sarcastic, and rude right up until the very end.