Fired from UPS years ago. Came back to say UPS is cutthroat

I had a random memory of how bad UPS was to me. I now work for DSNY sanitation in nyc. I have 4 years on the job. I lift 11-13 tons of garbage a day. But somehow this aint even half as bad as my short time with UPS.

I worked for UPS in manhattan for only like 2 months and i remember how abusive that job was. Now i probably wasnt the best employee because i was new, but i was willing to improve everyday and be a good worker. I remember working all day and afternoon no breaks and non stop walking and carrying. The amount of work they gave me was sometimes overwhelming and id get so stressed that i wasnt going to finish. A lot of responsibilities and minor things you needed to remember and do perfectly or you could get in trouble. I would sleep on the bus home from pure exaustion. Blisters on feet like iv never seen.

I also remember all the supervisors and trainers were miserable weirdos. One time a supervisor said to me. " oh youre taking lunch? you must not be dedicated to getting this route finished". Then another supervisor threatened me with physical violence because he was being disrespectful and i simply replied with "ok relax". I said what on earth kind of company is this. Then i couldn't find a tiny package because the loader put it in a weird place, and they fired me for that lol. Not blaming the loader it was probably my fault but still at least give me a warning or tell me how i can improve. It was such a blessing getting fired because i started working construction after which i loved, and then got on sanitation after and its so much better. i actually feel bad for UPS employees. Does anyone else have a similar experience?