For many families, it's a Thanksgiving tradition as rich as turkey stuffing or pumpkin pie: Rise before the crack of dawn the morning after the holiday, wait for the mall to open, and start hunting down Black Friday bargains. ... The Black Friday crush isn't for everyone, but the allure of a bargain speaks to human nature, consumer psychologists say. The limited-time-only nature of Black Friday triggers an innate fear of scarcity that drives people to buy, buy, buy. As long as these tactics aren't overused, marketing experts say, they can be very effective in luring holiday shoppers to the cash register with cartfuls of goodies.