so, responding only to the office work vs. manual labor work, I come at it from a different angle.
I had a (very little bit) of warehouse work as a teenager. I mean, real warehouse work where you get minimum wage for picking things up and putting them down again, assembling shelves, picking up stuff, etc.. - and I was exhausted at the end of those days in ways that I never am now, even when I do work that is physically more demanding, and I'm in my mid 30s with a body that isn't nearly as resilient as when I was 16.
I've done a lot of data center work that had similar physical challenges, often greater physical challenges; have you ever tried to rack a c6509? bastards are heavy. In fact, I've gone out of my way, and probably taken some pay cuts so that I still get to spend significant time picking things up, putting things down, and turning screws. I enjoy it in ways that I didn't enjoy that warehouse job.
The thing I want to point out here is that doing physically demanding labor while you are in a position to get paid a whole lot of money, like I am, is very different from doing physically demanding labor when you are getting paid very little, simply because respect, flexibility and the ability to ask for changes and exceptions scales with the rest of your compensation.
As a sysadmin, if I need a break? I take a break. Nobody gives me a hard time. There's no grope and grab at the door to make sure I didn't steal anything. If I want a tool or something to make my job easier, really all I've gotta do is find a link and send it to the boss and it gets ordered for me. If lifting something the standard way doesn't work for me? the boss gets someone to help me. My judgment on "yeah, I need a second pair of hands" is never questioned.
I mean, yeah, there are legal protections for minimum wage workers, and workers comp laws incent employers to make sure that they don't screw up employees too badly; but power differentials matter; As a sysadmin, while I'm not going to say I'm irreplaceable, if I walk, the boss will be noticeably inconvenienced. I get a pretty good say in how my job is done.
I imagine the same thing goes for being an independent electrician, or being a mechanic with your own shop vs. being a level one person in either one of those roles. Having the power to make exceptions in how you work, I think, makes a huge impact on how good or bad that work is for you.
I wonder if white collar work is the same way; if you are some minimum wage call center monkey with zero choice in the ergonomics of your workstation setup, is that way worse than being a programmer who can get a $400 keyboard and $6000 chair by just asking? My guess is yes, but I have even less time in the callcenter than I have in the warehouse.