I worked at McD’s for a few years in high school/college in the late '80s.
It really wasn’t that bad of a job. I learned a great deal.
I started when I was 15 years old. My restaurant’s policy at the time was to put all new hires to work for a few weeks cleaning tables and emptying trash, to see how they worked out.
After that, I deemed worthy enough for further training. Because I was under 16, I was put on the front counters. (My restaurant put all workers under 16, male and female, on front.)
Unfortunately, I was the only guy on front, and I felt rather self-conscious. When I turned 16, I asked to be trained for grill, but it never seemed to happen. (I was already trained and competent on front, so there was no real incentive for them to put me anywhere else.)
I therefore took every opportunity on slow periods to wander back to the grill, and get trained by the guy back there. I also watched all of the grill training videos on my breaks. Finally there came a time when there were too many people up front, and they were short on personnel on grill. I told the manager that I could do it, and was assigned to grill for the day.
After that, I was usually assigned to grill, and only occasionally on front. Some time after that, I picked up drive-thru. At that point, I could do every job in the restaurant, so I was made a crew chief. The variety certainly made the job more bearable.
After high school, I cut back to working there only on summer breaks.
After two years at college, however, I could make significantly more money working for my profs in the summer than I could working at McD’s, so I left for good.