Having a girlfriend is either the best thing or the worst thing in the world if you make your living in the markets, David Villalobos, a 21-year-old day trader based in Colorado, said. On the one hand, a partner offers something the market can't: companionship, an aspect of life Villalobos thinks many traders are deprived of. On the other hand, romance can be a distraction. Years ago, Villalobos was in a relationship in which his trading time plummeted from about 18 hours a day to zero. "It can