[keville]

https://missionlocal.org/2021/03/newsoms-experiment-to-get-r...

Linked in the article, too. While it's not the only source of the problem, it's still a big reason people get tired of looking around for a can in SF and just toss their litter.

[imglorp]

Same point with public toilets. People will eliminate their waste; it's up to the community to decide where they will put it.