RHETA JOHNSON I like to go back to Metro Atlanta often enough to remember why I left. Atlanta, of course, is now one hellishly dense suburb that stretches from Chattanooga to Columbus with a tightly stitched tapestry of chain crap and traffic snarls in between. I creep along and remember. In rush hour, it isn’t easy to find the motel where I’ll pay out the nose to stay one night for the reminder.