Early on, right after Gregor's transformation, he is most concerned about failing his family. The narrator says that he "hadn't the slightest intention of letting the family down." He feels that his real worth lies in his ability to work and support them, and he does not want to fail to provide. Later, in part 2, Gregor feels quite "proud that he had been able to provide . . . so nice an apartment for his parents and his sister." He certainly fears, now, that he will not be able to continue to keep them in the manner to which they have become accustomed. Gregor also has no wish to put his family out, to inconvenience them more than he already feels he is, and he will not even try to communicate to his sister that he doesn't like the food she brought him. In fact, "he would rather starve than call it to her attention." He attempts to be incredibly considerate of her and their mother's feelings.
But, by part 3, Gregor's feelings have changed.
At . . . times he was in no mood to worry about his family, he was completely filled with rage at his miserable treatment
Now, he feels resentful and even angry at the way they seem to ignore him and go about their own lives and, now, their own jobs. At one point, he even "hisses loudly with rage" at them. At this point, though, "It hardly surprised him that lately he was showing so little consideration for the others; once such consideration had been his greatest pride."