National culture exerts substantial influence on consumers' expectations, satisfaction, and evaluations. Despite that, within a service-based context, two cultures are met, that of the customer and that of the service provider, the existing literature systematically explores the effect of customer culture in isolation neglecting the impact of the provider's culture or their joint effect. We fill this gap by considering the concomitant effect of customer and provider cultural factors on passenger evaluations of airline carriers using a large dataset of reviews that covers the majority of countries. Employing a response surface methodology, our study provides significant advantages over methods based on cultural distance scores in revealing more complex non-linear relationships. This multi-dimensional approach provides new insights for assessing the impact of national culture on customers' service perceptions and evaluations, thus bringing significant implications for researchers and service providers.