I used to work in a pharmaceutical company where I had the job of meeting doctors along with medical representatives and answer any questions they might have on the drug (latest research, market feedback, latest guidelines, etc). It was an 8 hour job with slightly above basic pay. I got so good at doing this that my 1st boss asked me to train the local sales reps whenever I visited a city. I got to fly all over the country and together with the sales reps, tried to sell our brands. I was now in-charge of doing all that without a bump in pay or promotion (denied because “you’re not ready”). My seniors and colleagues actually asked my boss to promote me but he would never give a straight answer.
Time passed and I had built such a reputation that even the medical department sometimes asked for my help. My previous boss had secured a promotion and left the company without writing a recommendation letter. A new, overly eager guy came in his place and tried to make his mark by pushing us even more. I was doing presentations to doctors in my hometown when he asked me to go to a neighbouring town (3 hours away) by bus every week and train the guys there. Not only was I to do my hometown that day till noon but I had to travel 6 hours by bus total, train the team for 2 hours and finally go home an hour later by getting a cab back. In addition, he started adding Saturdays (non-working days) as well and used that to create motivation/blackmail/ competition amongst my seniors.
I finally had enough when he asked all that and started rejecting my plea for increasing expenses. I quit a couple of weeks after that. Everyone was surprised even the Marketing director (came to me later to ask about my aspirations or if I was going to their competition).
This boss finally called me in his room and asked me if he was the reason for quitting. I told him it was all that work with no pay bump. He told me that’s how things are done in this industry and if there was something else that could make me stay. I told him no. Heard he quit soon after.