I worked in a plastic factory for a few days...yeah it was absolutely soul crushing. I was placed onto a machine where the speed required to keep up with the bottles felt like a sadistic prank, and the shifts where 12 hours long. I was left on it by myself my first day being on it and it got to a point where all the bottles where falling off the machine because I couldn't. Then the lady in charge came over and told I'd be sent to that office if it happened again.
On top of that, the place was filled with plastic fumes and particle and didn't provide any breathing masks that I saw. Another lady there told her husband got fired because he got cancer and they want didn't want the liability.
Yeah, not the best experience.