A smiling customer is typically considered a happy customer. An in-depth analysis of the functions of a customer’s smile is nevertheless lacking. The current paper aims to fill this research gap by presenting a video-based study on salesperson–customer interactions that uses multimodal conversation analysis as a methodological and theoretical framework. Based on a deep investigation of real-life insurance sales meetings and business-to-business role play organized at a research laboratory and a computer-based algorithm analysis of the customer’s facial expressions, the study demonstrates that a customer’s smile should not be understood as simply signaling customer satisfaction. Our findings inform sales managers and the salesforce to consider customers’ smiles as a potential signal of customer’s discomfort, which should not be pushed too far.