Most every move in this market is exaggerated by the swings and whims of the HFT traders. Someone wants to sell and the traders amplify the moves. We are in a boring trending upwards market, where the moves are always done quickly and exaggerated, with an upside bias to the moves.
Every dip that is sharp, brings out those who now think the market will tank, because we really haven't improved the employment situation; but the market can live with 9.5% unemployment much easier than those who are unemployed. The unemployment situation keeps the deflation argument front and center, which keeps the Fed loose, which keeps QE II on the table, which keeps rates down, which keeps asset prices up.
The job situation still sucks, but that doesn't mean stocks will crash. They just ran up to resistance and needed to pull in a bit, and I really don't think we can have much more selling than this, because that's the story they want you to believe, and that's the story they will stick to.