Home ownership rate in the US had been over 60% for a long time. Because of that there is a high chance that your apartment neighbors grew up in a detached home and have no habits that apartment dwellers teach their children. Combined with the fact that apartments are usually temporary accommodations this can produce very disruptive neighbors.

This is not unique to America, all the countries that went through rapid urbanization that moved millions of former farmers from detached homes into city apartments have an archetype of a rural rube unable to accommodate to communal living with strangers.