Drawing on the social interaction model, we examine the mediating role that the customer's display of positive emotions plays on the relationship between the employee's display of positive emotions and the employee's positive mood. We also examine the moderating role that the customer's personality traits-agreeableness, extraversion, and emotional stability-play on the relationship between the employee's display of positive emotions and the customer's display of positive emotions. The results show that the customer's display of positive emotions mediates the relationship between the employee's display of positive emotions and the employee's positive mood. In addition, the customer's personality traits moderate the relationship between the employee's display of positive emotions and the customer's display of positive emotions. The customer's display of positive emotions depends less on the employee's display of positive emotions when the customer has high levels of agreeableness and emotional stability than when the customer has low levels of agreeableness and emotional stability.