Our neighbours from hell, who were in the apartment across the hall, moved out yesterday. No more all-night dance parties. No more hysterical lovers' quarrels in the hallway at 3:00 a.m. No more yapping mutt. The smoke detector -- which is set to go off simultaneously in 4 apartments, with a piercing sound designed to rouse the comatose and stone-deaf -- won't be triggered 3 or 4 times a day. They will not be missed!