In an increasingly complex and competitive world, business executives are focused on improving their understanding of their customers. Organizations today are fortunate to have a wealth of customer information at their fingertips. Hours are spent conducting surveys and focus groups, and in analyzing transactional, demographic and other data in an attempt to optimize the way they segment their customers and drive them to behavior. In our work, we have observed some commonly held, but often incorrect, views about customers. We call them the customer fallacies.