At the end of the worst day for U.S. stocks since December 2008, traders at Knight Capital huddled in groups, staring at their computer screens, wondering whether tomorrow would bring more pain. "It's scary, it really is," said Joseph Mazzella, senior equity trader at Knight, who had been watching the market's intraday lows, hoping stocks would stem their selling. "I hate it when the market closes below its low, as it sets the stocks up for a follow-through tomorrow." The atmosphere at Knight Capital in Jersey City, one of the biggest trading venues in the United States, was tense, and grew more heated into the ... (full story)