Mobility as a Service (MaaS) can potentially create positive impacts for sustainability and social equity: MaaS could steer user choices away from the private car, and increase access to transport options for all social groups. Though MaaS is not an entirely new concept anymore, in terms of user numbers, it remains a niche phenomenon. We aimed to identify factors that support or hinder MaaS use by focusing on the perspectives of both users and non-users, considering their personal situations, preferences, and needs. Specifically, we investigated under which circumstances MaaS can convince individuals to reduce the use of or discard their private car, using the theory of material possessions which asserts that the motives for (car) ownership are not only of an instrumental nature, but can also be symbolic and affective. We employed a qualitative research approach, focusing on the MaaS case in Berlin, Germany. Data was collected in 12 focus group sessions of 3 to 5 users and non-users, following a semi-structured guideline. The sessions were recorded, transcribed and analyzed using qualitative content analysis. Results show that socio-economic factors play a smaller role than expected, and use cases center around non-habituated trips. The added value of MaaS compared to regular transit apps was often difficult to discern or irrelevant. Even if MaaS provided perfect service and functionality, certain groups of car users would still not consider it, due to the vehement symbolic and affective motives associated with the private car. However, we found that individuals can associate symbolic and affective motives with MaaS as well. The most prominent lever for MaaS to contribute to a more sustainable mobility system seems to be emphasizing these MaaS related motives as well as the car as a burden, a burden which can be lifted by using MaaS.