My worst living situation was a different sort of bad from the places described so far in this thread. There were no critters or bugs - heaven forfend! It was clean, warm, dry, safe, and everything worked. But ...
When my first marriage broke down, around 12 years ago, my parents urged me to take the kids and move in with them. My mother had allegedly wheedled out of my soon-to-be-ex-husband, by pretending to be on his side, that he intended to kill us all and then himself. His behaviour regarding the divorce made this seem plausible, although I suspect now that it wasn't true. So, in my early forties and with three school-age children, I accepted the offer and moved back in with my parents. My oldest daughter didn't want to leave her school and stayed with her father. She was a strong-willed 14-year-old and then, as now, was the only person who could handle him.
Once I'd moved, I discovered that it was all about control. I was forbidden from having friends to visit ("we don't want strangers in our house"), leaving the house when my ex-husband visited to see the kids, cooking "smelly" food (anything that involved raw ingredients rather than just heating something up - there was no space in the kitchen for me to store my food anyway), going out in the evenings even after the children were asleep in bed ("WE have lives too, you know!") and even going out running for an hour after work. If you think a 40-something woman can't be prevented from going out for a run, you haven't met my mother in spate. I was expected to watch TV with them in the evenings. TV's not my thing, and the only computer in the household was in the same room as the TV and I wasn't allowed to tap-tap-tap ("thump and clatter") on the keyboard because it was annoying. I'd go off to my bedroom to read, and hear them complaining to one another about how unsociable I was. And my world contracted to that 11' x 7' bedroom. There wasn't enough room to put my belongings and I got nagged because it wasn't meeting my mother's standards of tidiness.
I did resist one thing. After we'd moved in, my mother suggested that I shouldn't work for a few months, but the thought of being without any form of income terrified me. Although I was too much of an outsider to be offered a permanent job, I got lots of piecework and insisted on continuing to work, holding my parents to their promise to get the kids to school and be there when they came home. And I managed to form a long distance relationship with someone who'd been an acquaintance for many years, and every few weeks I'd put the kids in the car and we'd all go and stay with him, and he'd come and visit us and stay in a nearby motel because he wasn't allowed in my mother's house. And Mum's never been an easy person - I'm sure my first marriage to a rather narcissistic man was a classic example of "marrying my mother" - and I walked on eggshells much of the time, but when I mentioned this she got mad and accused me of making her life miserable.
My son was badly bullied at school by another boy. The head teacher insisted that it was six and half-a-dozen. We knew it wasn't; my son is autistic, but has never been a conflict-seeker. The other boy was later jailed for murdering a much younger boy. I still shudder ...
And in the meantime my parents were entertaining themselves by helpfully checking out nearby houses for me to buy.
I made an impulse decision, bought my ex-husband out of the marital home (at a premium), contacted the kids' former school and asked if they could go back the next term, and nine months after running away I ran back. What a relief! Amazingly, my relationship with my parents recovered and they've rewritten history as if everything would have been fine had it not been for the bad boy bullying my son at school. I just smile. I'm good at that.
The experience affected me, though. Five years later, I moved back for a few weeks to support my father while my mother was in hospital. Dad didn't mind us going out on our own provided we were with him at hospital visiting times and at night. Whereas my sister was happy to go out running and to the gym and make her own food choices and take day trips to the city, I felt totally tied to the house and when I went out on my own I was anxious the entire time.