We know that the market is dynamic,as in it changes constantly,and as such,an investor who isn't careful enough to know when he is investing will fall in to heart problems or emotional trauma as a result of a massive fall in value,that is why it is important to condition your mind in a way that you won't get heart failure when you are at the loosing end.
Every investor knows there is risk in the game,and taking the risk is what shows you are ready to eradicate poverty from your life.