From “Broken Windows” by George L. Kelling and James Q. Wilson, who put forth the theory that urban disorder, vandalism, crime, and anti-social behavior can begin in the simplest of ways — with a few broken windows:
Consider a building with a few broken windows. If the windows are not repaired, the tendency is for vandals to break a few more windows. Eventually, they may even break into the building, and if it’s unoccupied, perhaps become squatters or light fires inside. Or consider a sidewalk. Some litter accumulates. Soon, more litter accumulates. Eventually, people even start leaving bags of trash from take-out restaurants there or even break into cars.
[via The Atlantic, March 1982]