Background: Satisfaction with services represents a key component of the user's perspective, and user satisfaction surveys are the most commonly used approach to evaluate the aforementioned perspective. The aim of this discursive paper is to provide a critical overview of user satisfaction surveys in addiction treatment and harm reduction services, with a particular focus on opioid maintenance treatment as a representative case. Methods: We carried out a selective critical review and analysis of the literature on user satisfaction surveys in addiction treatment and harm reduction services. Results: Most studies that have reported results of satisfaction surveys have found that the great majority of users (virtually all, in many cases) are highly satisfied with the services received. However, when these results are compared to the findings of studies that use different methodologies to explore the patient's perspective, the results are not as consistent as might be expected. It is not uncommon to find that "highly satisfied" patients report significant problems when mixed-methods studies are conducted. To understand this apparent contradiction, we explored two distinct (though not mutually exclusive) lines of reasoning, one of which concerns conceptual aspects and the other, methodological questions. Conclusion: User satisfaction surveys, as currently designed and carried out in addiction treatment and harm reduction services, do not significantly help to improve service quality. Therefore, most of the enthusiasm and naiveté with which satisfaction surveys are currently performed and interpreted - and rarely acted on in the case of nonoptimal results - should be avoided. A truly participatory approach to program evaluation is urgently needed to reshape and transform patient satisfaction surveys. Keywords: patient satisfaction, substance abuse treatment services, harm reduction services, patient-centered evaluation, service user perspective, user involvement