It's hard enough to feel that you made a stupid mistake, but when someone does something to you and puts you in a chair, that tends to be pretty hard to swallow. The staff is trained to recognize behavioral signs of these feelings. Depression and suicidal feelings are treatable and generally temporary. The psychologist helps you sort out what drives your behavior in ways that limit you, cause you unhappiness, or compromise the potential you can reach in the rehab process. Rehab doctors and therapists know they must adapt their approach to each person according to how that person is coping.
Some people are more energetic, gung-ho and motivated.
Some are depressed. Everyone does their best, and we try to motivate them and get them going. Some are able to do a little more early on, and we try to adjust for that. If someone isn't up for a vigorous weight lifting class or tires out we try to space things out to accommodate what they can and can't do. The fact that someone is depressed or angry while in rehab does not mean they will fail to adapt to disability.