Because I lived in apartments for my entire adult life until maybe 2 or 3 years ago, and I can say most apartments suck because of the neighbors. Ya my neighbors across the street from me are awful and trashy but they are not directly above me or one wall away from me.
Its mostly because all of the older apartment 20th ce try or older have wood floors that reverberate lime a drumhead. Newer buildings with concrete construction elminate noise. I dont hear my neighbors ever. Will never go back to an old building.