What makes Southern sweet tea so special?

"If ice was a luxury, then putting out a pitcher of ice-cold tea must have been quite a bit of hospitality. One historian, Joe Gray Taylor, wrote in "Eating, Drinking, and Visiting in the South: An Informal History" that the rural electrification—and, consequently, refrigeration—wrought by the Tennessee Valley Authority in the 1930s was 'probably more appreciated for the ice cubes it provided … than for any of its other services.'"