Follow-Up question:

I'm in the USA. My grandfather volunteered at age 18, early in the war but not immediately after Pearl Harbor. He informed the military that his profession was "farmer," and they told him to go home because that's where they needed him most.

Was this common for US farmers? Were they seen any differently by service members?

In which country?

There were plenty of men who were extempt from conscription due to their expertise being needed elsewhere.

In Sweden this included railroad officals and workers (who would be needed to handle railroad movement of troops and supplies), factory workers and engineers at vital industries (such as the Landsverk tank factory and SAAB aeroplane factory, but also SFKs ball bearing factory).

I think it was much more of an issue during the war when so many were in uniform that a man of military age out of uniform might be treated with suspicion. After the war, with most service members discharged, you'd have to ask to find out who served.

As another poster described, many were exempt because of critical war jobs. In some cases these jobs were secret (think Manhattan project). My own father worked at MIT's Radiation Lab, with thousands of others, including many young men who looked like they could/should have been in uniform, but couldn't even discuss their work.

Same as anyone else. If you're talking about the US, the Soviet Union, Britain, and so on, virtually everyone who wasn't directly involved in the war was still contributing, even if it was in an ancillary way. Roosevelt's socialist policies- particularly the building projects- were still roaring away, and major projects like power plant construction, hydroelectric dams and major road construction doesn't just materialize out of the aether. Factories had to be built, and American standards were quite a bit higher than German or Italian when it came to layout and design. It takes a lot of highly skilled technicians to make that happen. The Manhatten project wasn't just a bunch of European scientists escaping from the Nazis either. Roads had to be built, police were still needed, fire fighters were still needed. As it were, while you could entice ethnic minorities in the US and bring in labor from across the border to fill raw man power needs, you can't just replace an engineer. You can't just replace skilled labor. Training takes time. When Ford was paying assembly workers and machinists well in excess of market rates it wasn't as a point of benevolence, Ford did it because the money lost when said worker left and they had to train some new guy was even more.

In some respects the folks who stayed in the country were better off in the public eye- granted, the soldiers were all well received because of the amount of propaganda levied to remind everyone that this was a justified war- but usually when it came to that generation there was things that immediately changed everyone's perception of them. Even if we didn't call it PTSD back then, usually saying, "Oh, Normandy." or, "Oh, the bulge." Or, "Oh, Guadalcanal" and folks understood they'd seen some shit, to use common modern vernacular. At family reunions it was OK to talk to my own grandfather about WW2 because he flew in a bomber and hadn't gotten into the war till German air power had long been broken. Allegedly he'd never even needed to fire the machine gun he crewed. He got a million dollar wound when a flak round exploded outside his bomber, sliced through the hull, through his left hand, and out the bottom of the craft.

I had uncles who were navy men who served in the Pacific. You didn't mention Japan, Japanese people, Japanese cars, and sometimes even just Asia in general around them. If it didn't completely suck the life out them, they'd fly into incoherent rants and rages.