Black Friday. In the United States, it's the busiest shopping day of the year. Huge crowds gather outside their favorite stores at dawn, eagerly waiting for the doors to open so they can spend their hard-earned money.If you work in retail, it's also the worst shopping day of the year.But not for Doug. He's an optimist, a self-proclaimed "lemonade from lemons" kind of guy, and a horde of irritable shoppers isn't about to dampen his spirits. He's got his eye on an engagement ring for his girlfriend, Jenna, and today it's on sale. His hopes of popping the big question to her are more than enough to keep him going.All he has to do is make it through his shift.The shoppers are gathering. It's almost time to open. And there's a disheveled man dressed as Santa Claus staggering across the parking lot toward them?