What kinds of occupational complaints do service workers have?

It varies.

That's a very open-ended question. I've been on both sides of the union issue - having grown up in a solid union household and also being a manager in a union shop. The biggest frustration I had as a manager in a union shop was the irrelevant complaint/grievance.

-The Coke machine isn't filled enough

-Supervisor ___ picked up a piece of garbage and is stealing the janitor's work

But there were very valid union grievances/complaints, too.

- I should have been asked for OT - low hours, high seniority - but wasn't

- Contractor ___ isn't a union contractor and our contract requires that all contractors be union

All in all, about 50% of the grievances I heard were BS and 50% were valid. Just think of the things that you hear people gripe about... and you'll get an idea of the range involved in union employee complaints.