Behind the facade of many a New York City apartment building is the dissonant sound of residents complaining. The gripes that make their way to the inbox of my Ask Real Estate column offer a glimpse into how residents cope with the myriad irritations that come with living in cramped and costly homes. They include the co-op shareholder horrified by a neighbor’s rats’ nest; the parents whose building has barred them from using a stroller in the elevator; and the renter whose kitchen cabinets fell from the walls.