The stock market, just like life, can change on a dime.  In the market, just as in life, we must learn to adapt to change.  What separates the great trader from the rest of the crowd is his or her ability to change based on current market conditions.  In other words, NO EGO ALLOWED.  Mark Douglas, in his first book entitled The Disciplined Trader writes,
“There must be a difference between these two types of traders-the small majority of winners and the vast majority of losers who want to know what the winners know. The difference is that the traders who can make money consistently on a weekly, monthly, and yearly basis approach trading from the perspective of a mental discipline.  When asked for their secrets of success, they categorically state that they didn’t achieve any measure of consistency in accumulating wealth from trading until they learned self-discipline, emotional control, and the ability to change their minds to flow with the markets.”
We trade the current market conditions as they unfold with a plan to trade one way or the other.  To do otherwise would be to fight an undefeated foe.