Stress and frustration are big components in a physical therapist's day. Progress is slow and usually painful, and patients may take out their frustrations on the PT. The invective apparently can get to the point where the PT gets depressed and frustrated (about 10 percent give up and quit the field due to depression). And it's not just the patient drama that's a sore point in the professional life of a PT. Insurance companies are a fact of life, and much of a PT's day may involve sparring with insurance bureaucrats, and filling out endless paperwork.
Lots of PTs could use a couple of soothing massages themselves.