Non-adherence to medical advice is a serious problem to patients, health policy and practitioners. This article outlines concepts of behavioral economics that might lead a patient to decide against the provider's recommendations and thus to be non-adherent. Especially the timing of pay-offs and dynamic inconsistency, their uncertainty and ambiguity aversion, loss-aversion and numerous heuristics like the peak-end-rule are discussed. The paper concludes with some hints on “libertarian” paternalism that may improve the situation.