Type 2 diabetes treatment outcomes ultimately depend on patients and their ability to make long-term behavioural changes that support good self-care and metabolic control. Patients' perceptions about diabetes and diabetes-related complications can have a strong influence on their emotional well-being, as well as day-to-day self-care and the quality of metabolic control. The gravity of diabetes is often underestimated, and many patients do not understand the link between poor glycaemic control and long-term complications of the disease. Similarly, people with diabetes commonly undervalue the role of lifestyle changes and pharmacological therapy in preventing future complications. Negative emotions and preconceptions about treatment can also discourage adherence to treatment plans. 'Psychological insulin resistance' caused by fear and concerns about insulin and daily insulin injections can discourage many patients from starting insulin therapy, even if oral agents have failed. Depression, stress and anxiety represent further obstacles to optimum self-care and the attainment of glucose goals. Healthcare professionals should endeavour to understand and accommodate these issues when setting personal treatment goals and developing plans to achieve them. Importantly, the advice and support they provide should be tailored to the unique needs of each patient. There is scope to improve outpatient consultations to ensure agreement between patients and professionals concerning issues discussed and decisions made, and this may help to improve recall and motivation to manage diabetes. Engaging patients in the goal-setting process can help to overcome potential barriers to good self-care and may increase the probability that treatment goals are achieved.