Nearly 20% of patients are dissatisfied following well-performed total knee arthroplasty with good functional outcomes. Surgeons must understand the drivers of dissatisfaction to minimize the number of unhappy patients following surgery. Several studies have shown that unfulfilled expectations are a principal source of patient dissatisfaction. Patients contemplating total knee arthroplasty expect pain relief, improved walking ability, return to sports, and improvement in psychological well-being and social interactions. However, patients are typically overly optimistic with regard to expected outcomes following surgery. Patient expectations and satisfaction can be influenced by age, socioeconomic factors, sex, and race. The interplay of these factors can be complex and specific to each person. Published data on clinical and functional outcomes show that persistence of symptoms, such as pain, stiffness, and failure to return to preoperative levels of function, are common and normal. Therefore, the surgeon needs to help the patient to establish realistic expectations.