why does Gregoer changes?

The story begins as Gregor is looking around his room when he awakens, long before coming to any real understanding or acceptance of his condition, Gregor notes that it is "a regular human bedroom," though a bit small. In his normal accepting tone, Gregor seems to be expressing dissatisfaction with the size of his room and the conditions in which he lives. The use of the term "regular human" serves already to distance Gregor from everything human. Though he has not yet caught on to his transformation, he already feels removed from humanity. This raises the question of whether this distance is a result of his transformation or indicates his pre-existing distance from other people. No answer, of course, is given, and both are possible. There is a hint here that Gregor's entire metamorphosis may be the result, or the metaphorical equivalent, of his alienation.