While in China, I became obsessed with dirt. I had always been a relatively clean person before I went, but I've become a bit compulsive about dirt since I returned.
China is dirty and there is no way to get away from it. It is pervasive, it is in the air. The smog hangs in really thick clouds and there is a lot of dust, so laundry becomes dirty as soon as you hang it out to dry. My hands constantly felt dirty and I became a rather compulsive hand washer. My face never managed to feel clean. And, considering that my 5 liter shower heater gave me a maximum of 2 minutes of warm water in the winter, I rarely had a good bathing experience.
The best shower of my life was in China. It was in early December and I hadn't had a proper shower in months and a friend took me to a public shower. It was a little weird getting naked in public, but I was actually stared at less than usual. It was the showers attached to an old factory which used to be for factory workers, but was now open to the public (for a fee). It was steaming and huge. There was even a proper steam room in the back. I think we spent two hours in there washing our hair over and over again. There were also some attendants who would scour you down with a rough brush. I swear I came out 3 shades lighter than when I went in.
There really is a constant battle against the dirt in China. Most people prefer to have their windows open to get fresh air circulating through their rooms, but this brings in all the smog (not that it matters, if they're burning coal to cook). But there is a lot of pride in keeping a clean home, so people are constantly battling the dust. All of the middle class people I knew cleaned their homes once a day - sweeping, mopping, and dusting. It was easier because they lived in smaller apartments than we do in the US, but it is still work. When I visited families in the villages, they seemed to sweep their homes up to three times a day in an attempt to keep the dust under control.
The combination of being physically dirty and watching everyone else clean so much has made me hyper aware of dirt in my surroundings. While I didn't keep my space nearly as clean as a Chinese person would, I've brought back a lot of habits that are a little odd for an American. There is the nearly compulsive hand washing, but there is also a drive to sweep my floors really often. Right now, in the summer with the windows open, I am sweeping my floor five times a week. People seem to think this is a little excessive, but I'm not doing it 3 times a day.