The second that emotion can not be controlled is fear.

This is the scenario.

You buy all the safety and think that the market will rise, and even the analysis that I have to tell me it's time to buy. I agree to buy, and began to decline in the market and falling, and starts out panic and a loss of fear of another loss, only to find that the market actually started back up, even if you have stayed in the market I would have made a good profit.

But because of the fear of loss, and in fact I had lost.

Thus, emotions play a big role in the success of a profit.