The Onion gets it right. Cash Cab is great just because you get around all of those things like absurd payoffs for doing nothing, contestants who are merely archetypes instead of real people, and awkward commercial breaks. I don't think I've ever rooted against a contestant or group in the cab. I know for certain that doesn't apply to shows like The Deal, and Trivial Pursuit, even.
It also helps that the questions move at a decent clip, the payoffs are just right, and there's enough variation with the Red Light Challenge and the Video Bonus that the game doesn't become monotonous.