Yes, I think they do and it is not always to the patient's benefit.
I will use *me* as an example.

Now, I'm not going to go out and say that I am drop-dead attractive. I'm not. But, I am 42 years old, my weight is perfect, and thanks to good genes, I have a nice figure. I think I look every bit of 40 years old, but I think I look good for my age. I also wear clothes that compliment my figure and, even when I'm sick or going somewhere like the doctor's office, I will put on a decent outfit, do my hair, and put on makeup.
Many years ago, I was diagnosed with thyroid cancer. Earlier in the days of thyroid cancer treatment, a patient was required to become SEVERELY hypothyroid before treatments. So, I would be totally off my medications for a long time and my TSH would be at about 145. I remember going to the hospital and the technical having a fit because she said I "looked to good to be properly hypothyroid" and she didn't want to start treatments. I had to have extra bloodwork to prove to them that I was indeed sick.
More recently, I have found a new general practictioner to treat me. He is well respected and has a very good reputation. During my first visit with him, he went on and on praising me for "taking care of myself" and keeping my weight down and being, in his words "a very healthy 42 year old woman." He had no clue if I was healthy. I told him that I did very little to be this way and that, in fact, I felt like crap most of the time and laid out all my problems. Sometimes I feel like he REALLY refuses to take me seriously because I "look" healthy.