Why did Grete want to get rid of Gregor in The Metamorphosis?Towards the end of The Metamorphosis, Grete, Gregor's sister, was his caretaker, but...

Grete's quote and the feelings behind it seem especially
harsh in light of what you already observed -- she was his primary caretaker for the
majority of the story, but she sees how Gregor's existence is taking its toll on the
whole family, and she selfishly wants the hardship to end.  By this point in the story
she no longer sees the big bug as Gregor -- it is just a bug.  That is why she calls it
a monster and refers to the bug as a "monster" and uses the impersonal pronoun "it"
rather than "he" or "Gregor."  By distancing herself from the thing emotionally, she can
have a more detached attitude about the bug and can speak in a more callous way about
the bug.  By the time she says these lines the whole family has had to go back to work;
they have taken in and subsequently lost a group of boarders; and the family is tied to
this apartment because of Gregor.  She is young and she wants her life back.  She
doesn't want to be tied down to a bug that in no way reminds her of her brother.  At
first she recognized that the bug was Gregor and tried to bring him his old favorite
foods for example, but as time passed and the true Gregor never showed himself to her in
any way that she could recognize, she gave up on him ever returning to his old self and
she has just had enough of it all by this point in the story.  Sadly, Gregor hears these
remarks and gives up his will to live.  He was failing already -- living to the end of
his natural "bug" lifespan -- but these comments bring on Gregor's final sacrifice for
his family.  He lets himself go because he knows there is no more hope for
him.