It is said that our thinking makes things either good or bad. That the reality of life is dependent solely on how we choose to see the things that make it up. This explains a very important fact of life: our mind and its thinking process are responsible for 90 percent of our success in life. Positive thinking, therefore, is essential for success in sales and for our quality of life. Our mind is the most powerful tool there is. By itself, it is responsible for each of us being content or sad, determined or indecisive, strong or weak, positive or negative. The way in which our mind works, therefore, determines the way in which we feel and the way in which we act.