In the case of Kafka's Metamorphosis there is cultural significance in the importance of kids working as a means to support the family. This feeds into the stresses of Gregor both working and not working for his family. So, the themes of family duty and economy play a cultural role. I think theme of alienation and personal identity are more common human themes. Before his metamorphosis, Gregor is alienated from his job, his humanity, his family, and even his body, as we see from the fact that he barely notices his transformation. In fact, even his consideration for his family seems to be something alien to him, as he barely notices it when he loses this consideration at the end. After his metamorphosis, Gregor feels completely alienated from his room and environment and, as a symbol of this, can't even see his street out the window. The Metamorphosis, then, is a powerful indictment of the alienation brought on by the modern social order.