Therapists must plan sessions. I imagine that they look over the patient’s chart beforehand. It must be a bit more cut and dried for a physical therapist, whose session is modified only by the ability of their charge. For a psychologist, there may be a sense of what may happen during a session, but there are so many more variables.
The therapist below (no matter her specialty) is very concerned about her next patient and is putting a lot of thought into how the session will go.