What's the worst job you ever had?

I used to work as bar/waiting staff in a hotel, it was long, hard, exhausting hours and you literally didn't get to sit down more than the odd minute here and there. We'd end up leaning on walls when we could to try to get some rest! It was shit pay, we weren't allowed tips and the manager was a bully. He used to take great delight in tearing us apart in front of other people. Customers would often speak to you like a piece of shit and you just had to take it.
The only plus was some really nice colleagues.
- Closest I've ever come to waiting was a 7-11 clerk. It had its stressful moments, but most of the time, in the overnight shifts I got, the work was relatively light (outside of some restocking) and I could read.

"Recreational leisure assistant" at a leisure centre. Job was sold as being a lifeguard, needed to get a qualification first which was a fun week long course. Job was about 20% lifeguarding, 20% setting up the gym and 60% cleaning the whole bloody place. Only lasted a few weeks.

McDicks and Tim Hortons
After working at both I had tremors in my hand for a couple months after I quit. I've seen quite a lot of attrocious behavior from both my managers at the time and some entitled customers. The amount of stress for minimum wage is absolutely not worth it.🖕🗑️
Gonna be real; if those two fast food companies imploded today, the community and Canadians as a whole would benefit from shedding those hell holes.🌻
- Hello fellow Timmies survivor!
  
  🤗🙌

For a week in high school I worked in a call center as a telemarketer. Selling magazines. My best friend got suckered into it and, not knowing better, dragged me into it.
None of us got paid. They'd set up a call center in an office block, do like 4 hours of training, then make people cold call all day for two or three weeks. Then they'd shut down overnight, pull all the equipment, and move.
Evil operations. But it did give me a chance to see first hand (at like 15) that most people in those jobs were being exploited.

- Fruit packing is one of the hardest jobs there are in the west, there's loads of immigrants end up doing it in the UK cos nobody else will. You did well coping with that job.
  I did a double take about pizza hut clock outs is that even lawful?
  
  It's not lawful, but it's a common practice in the USA (and in Canada to a degree) because enforcement from the understaffed, underbudgeted department that's supposed to watch for this is spotty and it's just cheaper to pay the occasional fine than it is to pay your employees.
- Come Mr. Tallyman?
  I always thought that the person singing that song has an awful job.

Aside from the one I quit literally the same day I started (and thus didn't actually work there long enough to have a bad experience), it would probably be a summer role as a lifeguard at a public pool in Germany.
Young Asian-looking woman in a swimsuit in the heart of the whitest of the white. Ugh.
- Oh God. I recoiled. Jesus.
  I'm already sorry for what you had to deal with.
  
  This was in the early '80s too. I was "exotic" then.
  Thankfully my father taught me a few things about how to assert myself or I'd have had an even worse time. (For some reason my father knew exactly how men behaved. Funny, that.)

I want to preface my experience by saying the wage gap is a serious problem and women deserve to be paid the same as our male coworkers for the same job, not to mention women being overlooked for raises and promotions.
Early in college, I took a job working summers at a newspaper manufacturing warehouse for $7.50 an hour to try to get my foot in the door in the journalism field. The starting pay and job titles were the same for all the entry-level folks, but the actual work was sex-segregated, and they put me with the men, which really sucked. For the cis women, it was mostly standing in place, feeding newspapers into a machine and making sure there weren't any jams. On one occasion when I got randomly put on the elusive morning shift (which never happened again), I was put on the feeders, and it was pretty easy; the worst part was pulling out a paper jam since that would halt the whole production line, but that rarely happened. Otherwise, for the cis men and one trans woman (me), we would do the packaging and loading. It was two or three people doing a physically strenuous job that required more workers to perform optimally, with one person frequently calling in sick, constant multitasking/running back and forth, lots of overtime and a handful of OSHA violations, including me being expected to operate a forklift without being certified. I don't know why they didn't hire more people with certifications or spread out the tasks more evenly. Things were so frantic all the time I'm glad I never got hurt on the job.
It was a lot of overtime, with random scheduling often landing me in the graveyard shift, so I didn't have a social life during that time and I wasn't sleeping very well. I put my two weeks' the moment I was offered an internship writing and editing for a local magazine. The one positive is that I was in really amazing shape for those summers.

Personal assistant for the elderly. It should have been a rewarding job but it wasn't. The pay was awful, I spent more time travelling between homes than helping anyone, and the clients weren't the elderly people but the family who often just wanted a free cleaning service (it was a charity).
It was sad to see the elderly rot in their homes. The only excitement being my weekly visits that usually lasted only an hour. They rarely had anything else going on in their week and just had the TV playing in the background.
The families usually didn't bother with them. If they even had a family. And a lot of the people should have been in full time care but obviously didn't qualify for whatever reason.
I spent a lot of time wading through filth and piled up trash which hampered their mobility. A lot of my time was clearing it for them to be able to move uninhibited.
My final client I visited in the hospital just before they died. I'd spent a lot of time around them and it was difficult watching them die. I technically wasn't supposed to visit them but I figured it was the right thing to do. And when they died I sought another job. It was too emotionally taxing and wasn't paying a livable wage so I just couldn't continue with it. Ended up handed in my notice before I had something else lined up.
I can only pray that when I reach that age I won't end up in the same position.
- I'm in the safeguarding world, the elderly are horribly mistreated. Care is poorly regulated, and they're mistreated and abused in many ways. It can even result in their death, but is impossible to prove as so many staff are involved. What predators are realising is that if they target a young person, then the young person could get pregnant or credibly disclose at any point in their lives... elderly there's no pregnancy, they've less time to live and may have conditions that make their memory unreliable. It's awful
  
  Well, that's a pretty horrifying thought.

My first ever job was working as a cart pusher at a Walmart supercenter. I naïvely choose to work two long shifts in a row not realizing how much walking that is. Every shift would end with me having open blisters on my feet and I eventually just stopped showing up after a few months because I contracted cellulitis from having so many blisters.
On top of that management was very rude and unreasonable. Despite it being a supercenter, I was often the only person scheduled to work, especially on sundays, meaning I would have to deal with the after church crowd by myself. Usually I would show up to work and carts would be strewn all across the parking lot and none would be in the vestibules since no one was there to do carts until my shift started at 11.
Customers would yell at me to work faster and management would get upset with me since they were getting complaints too, even though it was their fault for having one person do a job that needs multiple people doing it.
Also some people would use the parking lot as a trash heap. People would come by and dump their broken junk that they couldn't put in their trash can in the parking lot instead of paying to dispose of it at an actual disposal site.