Simple statistics, not class, wealthy people are just as likely to be terrible neighbors, more people means more chances for terrible neighbors regardless of class. I've also been a renter numerous times. Nearly no one in a rental property wants to invest the hundreds of dollars into heavy landscaping when they could be evicted and most rental property owners won't see a return on investment so don't do it.

The neighbors I had were terrible neighbors but they were home owners that were close to my house. The fire department in question literally writes the rules for fires, despite more than one fire where children were killed in town they still never had a problem with burning roofing tiles, bonfires large enough to burn 30 foot trees, etc. While I agree with you that enforcing sensible rules is a way to make better neighbors it is still more likely that higher numbers of neighbors leads to higher possibility of poor neighbors.

I've lived in multiple cities in multiple states, nearly all in fairly nice apartment or shared spaces so I'm definitely not limiting my dislike to poor areas. I grew up relatively poorer than my area and have been fortunate to get where I am by a lot of hard work and good luck, I also spend much of my free time working to help disadvantaged people within my community. So while I can see how you might have mistook my writing as classiest it was definitely not intended as such, noise complaints with neighbors are super common, as are smoke leaking through walls and floors, animals not being properly trained (my wife was attacked by such a dog), property and shared expenses disputes are all more likely in shared property. Now much of this can be handled by a good landlord, however the term slumlord exists for a reason. While this doesn't bother some people it bothers me a lot.