Not quite a year ago I played as humans for a while for the hell of it. I also duplicated the goblin entries a couple times and renamed the new ones (hobgoblins and orcs), to avoid bugs.
Bear in mind this was back in 40d, when a single champion clad in iron was a match for a dozen goblins at a time- more, if you gave him steel.
Anyway, I had a "fort" of about 80 humans. They lived aboveground in skyscraper wooden houses, again, for the sheer hell of it. The entirity of thier trade goods consisted of socks. I wanted something different.
There were ten soldiers, and exactly ten suits of armor. No more, no less- if one died, he got replaced, but I had precisely ten soldiers, and no city wall.
Now, if someone died, I erected a statue on the spot and surrounded it with weapon traps, the number and material of weapons varying based on the combat ability of the deceased. Civilians got traps filled with no-quality wooden weapons (I'd added a reaction so I could get thousands of no-quality wooden weapons, mostly to train with.) When a soldier died, the traps that later surrounded the site of his death tended to take out quite a few goblins. These were the ONLY traps I used.
Now, this was a small embark and there was little to do, so everyone except the military was idle a lot after a certain point. I'd had some tantrums when invaders killed a few people, but they tended to be small and easily contained. Then one day I reached the saturation point where practically everyone was friends with everyone else. Prime material for an epic tantrum spiral.
One day, some invaders managed to take down a few of my champions through sheer force of numbers, then proceeded to get all up in my town and jack shit up (about half the military was sleeping at the time.)
The tantrum spiral was fucking amazing. It was the first I'd seen, and a thing of beauty. Before it happened I'd had about 90 people. Around a year later, I was down to about a dozen- four of which were soldiers, and one of the others was the fisherman, along with a few other random schmucks. Naturally, I had enough food and booze for that dozen to survive for the next century or so. So, just out of curiosity, I kept playing.
No migrants, and the non-military survivors were too busy burying and cleaning up to do much of anything else. This went on for about another year or two. I gave away massive piles of crap to the home city and whoever else came by, but I never got any more migrants. Eventually I got attacked again, by a huge force. They proceeded to wrestle my remaining soldiers to exhaustion through sheer force of numbers, and only then did they succumb to the invaders. They killed the remaining civilians, then left. All but one...
The fisherman.
Guy didn't give a shit about anything. He was one of the founding seven, and he had no family or friends. He just sat there by the river, periodically pulling out a fish and throwing it in the stockpile with the others, while more than two hundred corpses, human and invader, rotted into skeletons around him. That was it. He just sat there with his fishing pole, not giving a fuck, and with no cares or worries in the world. Guy just wanted to fish. He'd climb up the stairs, past the empty bedrooms of the other people who had lived there, to go to sleep, and he'd step around and on bones and bloated, rotting corpses on his way to get a drink or a meal, but it didn't bother him. Nope. Just him, his fishing pole, and the river. That's all he needed.
He sat there, fishing, for another two years. No more invaders- evidently they'd forgotten about the settlement, or considered it totally sacked, or something. I got caravans, but one guy couldn't bring enough stuff to give away to the caravans coming by to get immigrants coming again, so he didn't bother. Just look over his shoulder at them, give them a wave, and go back to fishing. No more migrants ever came.
So he just sat there, for another couple years or so. He was more than set for life. He'd never have to worry about providing for himself, with all the food, booze, and clothes left over.
Then one day, there were no more fish in the river. And he just got up, dusted himself off, and left.