An organization's success and even survival depends on its ability to fulfill its customers' expectations. Thus, understanding customers' expectations and especially the variables that influence these expectations are fundamental for any organization. The service marketing literature has given considerable attention to a wide variety of variables that influence customers' expectations. However, only limited attention has been given to customer demographic characteristics and personality. The purpose of this work is to explore these influences. Specifically, this work examines the influence of four personality traits (positive and negative affect, agreeableness, conscientiousness, and optimism/pessimism) and four demographic characteristics (age, gender, level of education, and income level) on two levels of customer expectations - desired and adequate. This book fits both practitioners and academics audiences. Executives and managers can use this work to better understand what their customers want. Professors and students can use this book to gain in- depth knowledge to the area of customer expectations.