One of the recurring devices in "The Twilight Zone," that classic treasure trove of madness and irony, was the "repeat sighting." In one episode, Nan Adams, driving alone cross-country, kept spotting the same ominous-looking hitchhiker every few miles. In another, schoolteacher Helen Foley kept seeing the same mysterious little girl in her apartment. Those riveting fantasies were entirely fiction. Funny thing is, though, we have "repeat sightings" in Bakersfield all the time. And even though we are, in one undeniable sense, poorer for it, we tend to characterize it strictly as a good thing. You've heard it, perhaps even proclaimed it yourself: Bakersfield is the biggest small town in America. Four hundred fifty thousand people live in this city and its environs, and yet we always seem to run into the same people.