I find it highly ironic that, if we examine this excellent short story carefully, we can see that by far the biggest transformation is not experienced by Gregor himself, but by his family, who suffer their own metamorphosis thanks to the change in their family life that Gregor's metamorphosis brings. The father is just one example. When he rushes in because of the sound that Gregor's sister makes, Gregor finds it hard to recognise him at first. Before, his father was always exhausted, incapable of standing up and could only walk slowly is a completely different person:
But now the father stood quite steady; in a snug blue uniform with gold buttons, such as attendants in banks wear; his heavy double chin unfurled over the high stiff collar of the jacket. From under his busy eyebrows, the black eyes gazed fresh and alert; the once disheveled hair was now glossy, combed down, and meticulously parted.
No wonder, then, that Gregor has a double take before he can identify that this man is the same father who has changed so much by the need to go out and get work and provide for his family.