In which we conduct a little scientific experiment—on tape, with hidden microphones—about whether niceness pays. We wire two waitresses with hidden microphones. They're superfriendly to half their tables; and aloof to the other half. They examine their tips to see which generates more profits. Thanks to owners Jason Hammel and Lea Tshilds and the staff at the Lula Cafe in Chicago's Logan Square neighborhood. (10 minutes)