Gregor's transformation into the monstrous vermin can described as the transubstantiation of his body to match his obsequious and subservient personality. Gregor is a typical workaholic stuck in a dead end job, trying to provide for his family. He does not seem to have the courage to stand up to his boss or his family. His parents are the ones who have the debt with Gregor's boss. There is no reason why the father is not capable of working to pay off their debt. However, as long as Gregor works without complaint, he does not have to. The fact that arthropods are literally spineless creatures seems to fit Gregor's personality perfectly.
Although Gregor is the main provider of the family, his father is still the head of the household. At the end of each of the first two sections of the novel, Gregor is being chased back into his room by his father.
His father never seemed to appreciate his work before his metamorphosis and after, he seems to want to be rid of his son. When apples are being thrown at Gregor, he merely cowers into the corner, just as he would if confronted as a human.
Once Gregor became a bug, his voice was no longer comprehendible to the human ear, but his voice was never truly heard by anyone before his metamorphosis. His boss never heard Gregor's voice since his salesman had to be exceptionally close in order for the boss to hear them. He ordered Gregor around and the harder Gregor worked for the company, the more work was expected of him. He does not miss a day of work for five years, yet his boss has a conniption when Gregor is late one day. Gregor cannot distinguish himself in the eyes of his...