Depends on where you are. San Francisco absolutely has a real, extremely-visible problem in a number of places. In a "walk from transit to work, you'll see it quite literally every day for years on end" kind of way.
When it rains, a significant amount of the Market Street area (and surrounding blocks) smells like pee for a day.
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Part of the issue with the "perception vs reality" claim in big cities is that people who live near-ish to places with issues like this avoid those places, either consciously (x area is dangerous so don't park there) or subconsciously (none of your friends go there, so you don't know anything there, and have no reason to go randomly). Visitors and new arrivals are pretty often more likely to encounter it at a more accurate rate.
When it rains, a significant amount of the Market Street area (and surrounding blocks) smells like pee for a day.
---
Part of the issue with the "perception vs reality" claim in big cities is that people who live near-ish to places with issues like this avoid those places, either consciously (x area is dangerous so don't park there) or subconsciously (none of your friends go there, so you don't know anything there, and have no reason to go randomly). Visitors and new arrivals are pretty often more likely to encounter it at a more accurate rate.