According to Mark Douglas
In any particular trade you never really know how far prices will travel from any given point. If you never really know where the market may stop, it is very easy to believe there are no limits to how much you can make on any given trade. From a psychological perspective this characteristicwill allow you to indulge yourself in the illusion that each trade has the potential of fulfilling your wildest dream of financial independence. Based on the consistency of market participants and their potential to act as a force great enough to move prices in your direction, the possibility of having your dreams fulfilled may not even remotely exist. However, if you believe it does, then you will have the tendency to gather only the kind of market information that will confirm and reinforce your belief, all the while denying vital information that may be telling you the best opportunity may be in the opposite direction.