What is it that prevents a prospective customer from making a purchase even after they have conducted a lengthy evaluation process? The reasons may surprise you. Regardless of the prospective customers' confident demeanor, on the inside they are experiencing fear, uncertainty, and doubt while making their selection. The stress this creates serves as the key factor in determining whether or not a purchase will be made. Therefore, all salespeople need to understand this lowest common denominator of human decision making. They need to understand the nature of stress.