My first 'real' job in HS I worked in the warehouse at Circuit City as seasonal staff (getting ready for the holidays) in 1998/99. 5am Saturday truck unloads, snotty people pissed that you can't fit a 32" CRT in the back seat of a Honda Civic, getting 100+ pound TVs from 3 stories up. Eventually I got the happy talk that I was no longer seasonal, I was sticking around- I was the only warehouse guy that got that and I was proud, even though it was $7/hr job with me carrying heavy shit, my work ethic was being acknowledged.
You learn a lot about gracefully doing things you don't really want to and finding a way to be the best you can be at the task at hand and deriving your satisfaction from doing the best you can, knowing that you gave it honest effort. I hustled my ass off, it was mindless, things were heavy and I was the big strong guy- that meant I got 90% of the fridges and rear projections and monster CRTs (looking at you Sony). I became 'that guy' for something, I had a 'skill' useful to the business that stood above others, that became my motivation. Do good work, stand out with quality.
Follow that with stints as a motorcycle mechanic, a farm hand on a dairy farm, a job site laborer, and a summer doing roofs- there's literally nothing I can be asked to do in an office environment that is more grueling or requires more effort than any of those things- and I pay more in taxes every year than I probably made at all of those jobs combined.
I've been in the middle of some pretty shitty projects where I was having to give people the pep talks to keep them from quitting or to see it through to the end. 24+ year old 'adults' literally crying about not being able to take it anymore. I don't look down on them for being emotional, hell, I don't look down on them at all, but my first thought every time is you have no idea what a tough day of work really is.
As an aside, I'm not talking about not being able to handle harassment or some type of political infighting or all of those interpersonal issues that can have real and lasting emotional consequences. I'm talking about a shitty project or grueling stretch of work that has gone sideways that has everyone working long hours to try and save it.