Night shift has some interesting types. Not only are the night-owls in the U.S. a bit different - the people overseas who bother to use the internet for intelligent conversation tend to be very interesting types, as well.
We also get the people used to the coast-to-coast AM. The types who used to stay up late and chat around the fire are the same types who man the night watch while everyone else sleeps. There's a certain symbolic resonance to it that is hard to overlook.