Hardest physical work - Roofing. Back-breaking gig of spreading sticky tar with a mop over a flat, reflective roof in Florida's summer sun was probably the most difficult physical labor in my life. I surely couldn't do it these days. Additionally, half of the crew I worked with was drunk, half were surly and half didn't speak English to me. (those halves were not exclusive of one another, math nerds.). Who the heck drinks alcohol all day in the sun? Why be mean to people that are trying to get by? I can understand not speaking the language - but working with someone that doesn't have a common tongue can be a challenge for me - I like conversation, at least every here and there.
But... I don't think that was my worst job.
I've had a couple of jobs where my boss was abusive. The chief of one marketing company I worked at had some very serious mental problems. Off the top of my head, he - threw a mug at the head of his pregnant daughter-in-law, bullied his employees - including, but not limited to: yelling at the top of his lungs / threats of physical violence / calling the sheriff on folks that he hired as cheap labor - who were illegal aliens. (that's how he got out of paying them any benefits).
That said, before I left that workplace - it was comical to see people stand up to him. He was such a classic and stereotypical bully that he didn't know how to react when someone didn't react in a cowed fashion.
He called a dock worker out to fight, and the dock worker agreed... asked him to step outside. Bad boss responded by calling the police, claiming that the dock worker threatened him. When the big boss asked for witnesses, the entire staff refused to bear witness for him - told the truth, in that he'd called the guy out. The cops still escorted the worker off the property, but it made the big boss look like a complete feeb - and it crushed his bully-boy spirit for a few days.
Later on, he was tried, and for the most part, found guilty for all sorts of charges hundreds upon hundreds of thousands of dollars, maybe into the millions owed to clients, employees and the irs - for details there's good ol' public records
for both palm beach county see here - (see especially tax evasion) - and broward county (contract indebtedness for the most part.)
The thing was.. if you removed that crooked and cruel boss-guy from the equation, it was a really good gig. My immediate leader was a good friend, and despite his being the nephew of the owner, was about as good a head honcho as I've ever seen. Strong work ethic, good with people, and able to take care of business. He's now working in Guantanamo Bay... and I suspect that he's a heck of a lot happier!
Either way, I have long since moved to greener pastures, and I know I'm better off as a result.