Political mass polarization is a major concern in many democratic societies. Yet, societies can be polarized with regard to policy issues, on ideological grounds regardless of issue positions, in the form of partisan affect or all at once. An array of research has shown that these different forms of polarization do not only manifest themselves in a lack of understanding for divergent political convictions but in an avoidance of interactions across lines of difference all together. Given the increased importance of political conversations across lines of difference in light of contemporary research on polarization, this paper revisits the question: To what extent to people avoid having political discussions with others due to political differences? We disentangle which forms of political differences prevent political discussions among ordinary citizens most. Using a uniquely-suited dataset from a German metropolitan area containing georeferenced survey data on respondents and their everyday political conversation partners, we are able to simultaneously study disagreement among political discussants with regard to salient policy issues, ideological positions, and their partisanship. We use a case-control design to analyze how different forms of dissimilarity affect the likelihood of two people discussing politics with one another. We find that dissimilarities on all dimensions (independent of one another) strongly decrease the probability of political conversations taking place. Differences in partisanship exert the strongest effect on the choice of political discussants - especially among politically highly-involved citizens, pointing to the relevance of partisan affect as structuring factor of everyday political interactions in multi-party systems.