Investors in the stock market should consider who benefits from volatility. It is certainly not the individual investor. The unfortunate tendency of individuals is to buy high and sell low. Volatility and the fear of losing money go hand in hand to force the investor to sell at the worst time. Hedge and mutual funds and other professionals exploit that behavior to capture the drive profitable trading. Individual investors need a professional advisor who helps them stay focused on their long-term strategy.
You can read more about the conflicts of interest that most mutual funds have in exploiting fear, greed and volatility in this article published yesterday in the New York Times by the chief investment officer of Yale.