The article discusses the subject of the identity of the inhabitants of Polish Upper Silesia from the perspective of micro-history and the history of everyday. By analysing selected court files concerning contempt of the state and Polish nation from the 1930s in the city of Katowice, I show how everyday life at the time was undergoing nationalisation and politicisation. In the face of the rivalry between Polish and German nationalism, family and neighbourly disputes may be interpreted in national categories, and the feeling of bitterness caused by living conditions may be treated as contempt of the state. The identity and political interpretation of seemingly unrelated cases becomes a tool in the hands of the Polish authorities, but the Upper Silesians themselves also use it for their own purposes.