Friday marks the official start of the holiday shopping season. Or rather, it used to — more and more stores are opening on Thanksgiving. That's why, at 6 p.m. Thursday, Albert Boscov, 85, will head to one of the company's 43 stores. "We don't like opening on Thanksgiving, because we screw up life for people," said Boscov, chairman of Boscov's Department Store, now celebrating its 100th anniversary. "We're open now because we have no choice," he said. "The business is so big, those few days that if you aren't open, they'll go somewhere else."