The last woman I studied with was disabled and lived in a one room apt. So I sat on a chair next to her bed and next to that was her dirty filthy stinky potable toilet. Right next to that was a little counter with dirty dishes, old food and well you can imagine that "martian death" stuff. We studied for about an hour and then I usually spent an hour washing dishes and emptying her pot. I didn't dare take my kids there. Really really sad.
Then when I was younger my parents pioneered where the need was great in a very very rural area. Many inbred folks who had never even been out of the holler they lived in. It took 4wheel drive to get to these places. Several homes had dirt floors. One charm school graduate chewed tobacco and spit into a wooden bucket next to his chair as if that wasn't bad enough, when he felt the need to blow his nose he just leaned about 3ft over the bucket and blew on in there. Some really crazy stuff going on with the DNA there too, one family all had two sets of teeth over top each other( I am not talking about over crowding here, no, they had 2 sets). Does not make for sweet smelling breath.
Then once we went to a study's house for dinner (nice gesture). The smell was so awful my eyes watered and then my mouth, no way could I eat anything. The study said "what's wrong honey is it that smell?" then she proceeded to chastise her son for not cleaning up several dead rats that had apparently accumulated in the kitchen cupboard.