Walking down the street in SF near the Caltrain station, right on the street in a parking space I saw a huge pile of discarded construction of waste wood, with exposed nails and sharp edges. In any city with functioning cleaning services, this would trigger a cleanup response, since it is unsafe and a nuisance. Yet this pile of crap appeared to have been there for quite some time.

To me this is the soft version of the broken window theory. If your city can't care enough to clean up its messes, yes people will treat the whole thing like a trash heap.

Contrast.

In Shibuya every single night, 365 days a year, drunk people puke and toss waste all over an area about 4 SF city blocks. Every single morning a team of govt workers clean it to fairly acceptable levels. The homeless also congregate under the nearby train tracks, but there are so many public FREE toilets that no, I have never seen shit on the street.

SF is dirty because the people prefer low taxes to real government services. Shibuya CITY tax is hefty and rises considerably if your income is above a certain level, maybe 100k, I forget the exact numbers.