Not exactly a doctor, but a dentist, which I guess counts.
We (My mom and I) went to a black dentist who worked in the ghetto and I was the only white guy (I was 10-11) there. So we waited in the waiting room for about 2 hours. We finally got in a room, and we had to wait 2 more hours for the dentist, since he had started treating (black) patients that got there much after us (racism).
Anyways, FINALLY the Dentist came in (I'm now positive he was a sadist). He introduces himself, and begins his work. Immediately I noticed something was off with him. He started by picking out "between my teeth" using a sharp metal tooth pick, and given he didn't really pay attention while doing it, constantly missed, painfully poking me in my gums (he didn't give me any anesthetics). After he was done with that my mouth was sore and in moderate pain, but it either didn't matter to him, or he didn't care.
After that it was time for him to do something different, but much more stressful (I think he was supposed to be drilling a cavity). He kept putting too many things in my mouth (tubes, lights) while my head was tilted black leaving me unable to swallow. Couple this with the fact that I had saliva building up meant that on more than a few occasions I couldn't breath. After a few times of me not being able to obtain a valuable life-sustaining resource we told the doctor to be more careful, but he either didn't really listen, or didn't really care.
So not too long after our plead for finesse it came to be that I couldn't breathe again. Then I REALLY couldn't breathe. No matter how hard I tried for what seamed like the longest time I couldn't breathe. I was looking at the doctor in a way to signify "MOTHER FUCKER I CAN'T BREATHE" but either he really didn't notice, or really didn't care.
So what it took was for me to look at my mom like this for her to walk over from where she was standing and tell them to take the stuff out, and when they didn't comply she took it out herself. After swallowing my spit and letting in the first air of my life, I gasped out a wheezy "WHaT thE FuCK is WroNG wItH YoU!?!". If my mom didn't act I possibly would've died, or at least had a much more traumatic experience.
After that we finished up, (very carefully keeping an eye on the dentist) and never came back. Then we ate KFC because we were just there for about 5 hours.
Tl;dr Went to Dentist, waited 4 hours, then almost get water boarded by my spit, ate KFC.