Trading should be reactive as opposed to being predictive. The problem is when traders assume they know what is going to happen next. Now, I may look to StockCharts of positions I have and see that say, the stock is going down, I have a put option trade on it and a rational assumption unless, proven otherwise, is the trend will continue. So, my stop loss is not hit and it continues going downward. I did not know that ahead of time. It could have just as easily, gone up and blew thru my stop loss, exiting the trade. That is the reason you have stop losses because you do not know what will happen next. That way, you got your bases covered.