[wingworks]

I'm sure it depends on demographic/country etc, but I've lived in Apartments where everyone was considerate, no loud neighbours, no smokers. Everyone just peacefully co-existed. (I've also experienced the opposite, and unfortunately, it is more common.)

[socalgal2]

And I've lived in apartments designed to be much more sound proof, then the neighbors could do whatever they wanted and didn't have tip-toe around each other.

[fragmede]

This is the way. I was a great neighbor, back when I lived somewhere with concrete walls between the units. Also, db meters on ebay are great peace of mind. Mount one on your wall and find out how loud is loud enough to be heard.

[AlwaysRock]

All it takes is one good neighbor moving out and a bad one moving in next door…

[JoshTriplett]

Exactly. 8-9 people out of 10 are just fine. 1-2 out of 10 (likelihood multiplied by the number of shared walls/ceilings/floors you have) are enough to never want to share a wall/ceiling/floor again.