Prior research suggests that employees benefit from highly passionate teammates because passion spreads easily from one employee to the next. We develop theory to propose that life in high-passion teams may not be as uniformly advantageous as previously assumed. We suggest that high-passion teams also evoke pressures that lead employees to expend effort to increase their levels of passion, which negates the benefits the team provides. We first conducted an experience-sampling study at an engineering company involved in the production and maintenance of critical infrastructure that benefits the greater good, with 829 employees nested in 155 teams, which we surveyed three times per day for 20 consecutive work days. These data show that employees caught their teammates’ passion and consequently reported better performance, lower emotional exhaustion, and a stronger sense of social connection. However, these benefits coexisted alongside costs employees incurred that were associated with increasing their passion. In a subsequent pre-registered experiment ( N = 1,063), we provide causal evidence for these effects and their underlying mechanism, finding that passion contagion is particularly effort-laden—more so than contagion of other states and increases in passion that are not the result of contagion. We develop a theory of differentiated passion contagion that exposes the effort inherent in contagion and the implications of that effort. Our work suggests that passion caught from others may hold less value than passion incited from within, and shifts our understanding of when and why passion for work is beneficial and detrimental. We also discuss implications for broader emotional contagion theory.