If a product is easy to use, it makes the user feel competent. Feeling competent is one of the most critical factors in being motivated to continue a task. Being frustrated leads to feeling incompetent, which in turn leads to abandonment of the task. That is why ease of use is so important in the industrial design of medical devices used by patients as part of a treatment regimen. Easy to use devices not only make for the best experience, they also instill in the user a sense of competence. Feeling competent is a strong motivator. And maintaining a patient’s motivation is an enormous contributor to compliance.
For more, read what Mark Clare has to say about competence and the other key factors that influence motivation.