Sometimes it's a one-time event that causes business to grind to a halt. In 1995, it was the O.J. Simpson trial verdict. From Alan Dershowitz's book on that moment in history, "America on Trial": "Work ceased in factories, in post offices, and in surgical suites of hospitals. It was the most unproductive half-hour in U.S. business history, costing an estimated $480 million in lost output." Trading volume on the New York Stock Exchange dropped by 41 percent, the book said.