Purpose The purpose of this paper is to evaluate the nonlinear impact of users’ memories on their general evaluation of outpatient healthcare services by the integration of two methodologies: critical incidents technique (CIT) and penalty-reward contrast analysis (PRCA). Design/methodology/approach The authors carried out a survey with 356 respondents, users of seven outpatient clinics located in the city of Blumenau/SC, Brazil, during 2016. The participants were asked about their perceptions of positive and negative aspects of the service; and, using CIT, the answers were categorized according to the following dimensions: empathy, communication, facilities, access, promptness, medicines availability, complementary services, safety/confidentiality and service performance. Then, the authors evaluated the nonlinear impact of critical incidents on users’ general evaluation of the service using the identified incidents as input variables in a PRCA. Findings The findings show that users of healthcare services tend to remember emotion and health aspects positively, while technical and formal aspects tend to be more negatively than positively remembered. On the other hand, PRCA identifies that incidents of three dimensions positively influence the overall perception of the service (empathy, complementary services and privacy) and five negatively (empathy, facilities, speed, drugs/pharmacy and health performance), explaining 26.3 percent of the variation in clients’ general satisfaction. Originality/value The present paper explores the integration of two methodologies, showing how we can use open listening to healthcare service users to identify the nonlinear impact of different incidents on their general evaluation of the service. The results show that what customers remember does not necessarily influence overall customer satisfaction. The present approach allows companies to improve the process of listening to customers. There are no other papers exploring this approach, particularly in relation to healthcare services.