I've worked part time at Morrison's since I was 16 (now 19) whilst at college and I hate the place, I've had so many issues with them, mainly regarding scheduling, like they'd just put me down for a shift without notifying me, or changing my hours, again without notifying me, even though really I shouldn't have to check the schedule at all as I've got a contract, you and the dept manager are also supposed to initial it saying you've agreed to it, eventually got a disciplinary about it. I explained they'd just put me down without telling me, I never initialed it, them changing my hours which I could prove etc but still got a verbal warning from the most illogical manager ever who just kept repeating "The onus is on you to check the schedule regularly".
I also wanted to change my contract hours to suit my new college timetable this year so asked my dept manager months in advance if we could work something out, he goes, yeah I have enough hours to do that, just work really hard for me for the next few months and I'll change it. At the time I was doing 3 closedowns a week on produce for him, often staying upto an hour extra making sure it was really good, did this for a few months and in the end he made up some bull about how he would trial me or something and basically when I moaned he made it out I was crying as I couldn't get my own way.
I'm also a relief cashier and I've sometimes spent almost 3 hours, in a 5 hour shirt on tills yet still expected to do a perfect closedown etc.
We also had a new supervisor on Produce for a few months who often would do up to 10 hours+ extra a week (unpaid) and in the end quit the role and his job and is now much happier for doing so after finding another job.