I see this in some cities. They are very clean looking, no litter, no graffiti, very shiny windows. Then you think about how the people must be treated to make this be true.

> Then you think about how the people must be treated to make this be true.

People who have all their needs met (food and safety, social, etc) tend to want to make the world around them better. I would wager the nice looking places are more likely to have well-treated people.

Places that look like dumps are the ones more likely to be populated by people who are treated poorly.

https://en.wikipedia.org/wiki/Behavioral_sink

TLDR; they built a mouse utopia universe 25 with plenty of food water and space . Eventually some grew violent, others sat and groomed themselves all day, they stopped breeding and died out.