My previous/first part-time job was a cleaner and most of my colleagues were old women. On paper the job was brilliant because there was no annoying customer interaction, good pay + I got weekends off.
However the manager guy basically abused the fact that I was young and desperate for work by giving me the most work to do out of everyone, and so when I didn't complete the work up to standard he would criticise me nigh on every week.
It got to the point where he switched me round with this other woman. I was able to do her work in under half the time it took me to do mine, but I didn't do that for long because I switched back to my old shift. Why? Because after
three shifts she was on the verge of tears because it was too much work.
So I get moved back, manager does **** all about my shift and continues to scald me when I can't do my work in time. The work was perfect all except for the fact that the manager was corrupt and gave all the old employees less work to keep them happy and lumped it all onto me.
The funny thing is that, quelle surprise, the person who took over my shift after I left was a student. The person who did my shift before me was a student, and so was the person before them

Got a new part time job now so it's all good.