The increasing human-robot interactions across service domains require an examination of their moral challenges, particularly from the user’s perspective. This study explores how efficiency and morality intersect in deploying service robots during the customer encounter. Utilizing a mixed-methods approach, we examine behavioral and attitudinal customers responses to service robot morality. In a field study, we uncover a trade-off between efficiency-oriented and moral robots, varying based on product involvement (Study 1). Customers prefer moral robots for high-involvement products and efficiency-oriented robots for low-involvement products. In a subsequent laboratory study (Study 2), we focus on a high-involvement retail scenario to elucidate the underlying mechanisms of customer responses to moral service robots. We demonstrate that experienced robot morality benefits relational interactions by increasing customer trust. However, in transactional interactions where customers prioritize robot functionality, experienced robot morality can lead to drawbacks. By demonstrating the inadequacy of a one-size-fits-all approach to robot morality, we underscore the importance of adopting a customer-centric design for moral service robots and show that the effectiveness of their placement depends largely on the type of service encounter. These results can serve to guide managers and robot designers towards aligning robot morality with customer demands, facilitating positive human–robot interactions.