The common theme in many of Franz Kafka's stories is Alienation.
Explanation:
Franz Kafka was a famous novelist, fusing realism and fantastic elements in his works. His characters are mostly seen facing some bizarre or surreal situations. And his works mostly deal with the exploration of various themes that greatly deal with alienation. This alienation may be from the society, from people around us, and may even be from our own selves. To him, society is the most frequent and strongest alienating factor that needs to be taken care of. Societal alienation is the biggest hindrance to the progressing of our true identities and this alienation, when changed or remedied, will eventually bring about the betterment of the person and the society as a whole