This paper explores the dynamics of emotional arousal during service encounters and its impact on customer response. The authors identify four key features of arousal variation: the peak (highest arousal level), the end (arousal level at the last part of the encounter), the trend (change in arousal level over time), and the skewness (frequency of lower arousal levels relative to higher ones). Using electrodermal activity (EDA) to measure arousal in real-time, the study finds that a higher peak arousal level and a more positively skewed distribution of arousal levels predict increased customer approach response, such as spending and unplanned purchases. However, the end and trend in arousal level did not significantly affect customer response. The research contributes to the literature by advancing understanding of how variations in arousal over time influence customer experiences and provides methodological insights by capturing arousal in situ using EDA. Managerial implications suggest that firms should design service encounters to create highly arousing moments and maintain a balanced distribution of arousal levels to enhance customer engagement and satisfaction.This paper explores the dynamics of emotional arousal during service encounters and its impact on customer response. The authors identify four key features of arousal variation: the peak (highest arousal level), the end (arousal level at the last part of the encounter), the trend (change in arousal level over time), and the skewness (frequency of lower arousal levels relative to higher ones). Using electrodermal activity (EDA) to measure arousal in real-time, the study finds that a higher peak arousal level and a more positively skewed distribution of arousal levels predict increased customer approach response, such as spending and unplanned purchases. However, the end and trend in arousal level did not significantly affect customer response. The research contributes to the literature by advancing understanding of how variations in arousal over time influence customer experiences and provides methodological insights by capturing arousal in situ using EDA. Managerial implications suggest that firms should design service encounters to create highly arousing moments and maintain a balanced distribution of arousal levels to enhance customer engagement and satisfaction.