For those few folks that love to deal in investments because it is aligned with the ebb and flow of their existence, fine, be merry in all facets of all stock markets because playing the game is no more than dealing with yourself and how you make decisions. For the majority of folks that invest it seems they are in the game for the wrong reasons or their actions are not aligned with the true purpose of their initial investments: to accumulate capital to provide for themselves many years from now in their retirement. So, the average retail investor risks his or her account value today and allows his or her investment holdings to diminish by refusing to sell this decision is contrary to providing for yourself. When the day comes that the Dow and S&P 500 index fail to regain about half what it loses after a large drop and deviates from the pattern of partial rebound, that is the signal, or perhaps evidence, that the crowd of players no longer has the will to risk as foolishly or the capital to play the game in the same way: the market falters for the long-term because the players perception shifts: they look for other games.