My worst job was the summer between first and second year of med school. I worked as a phlebotomist at a local plasma donation center - very depressing place - people came and gave blood for a paltry amount of money. There were about 10-15 of us from my class working there during the summer. Unfortunately, several of my classmates exuded superiority from every pore. This cast a bad light on all of us - you know the privileged and educated (yeah right - educated maybe, but certainly not privileged). I still remember the feeling I had when I couldn't "get" a hard stick one day and one of the full time workers had to help me. She was so full of scorn and derision that I, who was going to be a doctor, couldn't do this.
It was the first (and perhaps only) time I felt hated for what I was rather than who I am.