The Metamorphosis

Guilt stems from family duty, and is Gregor's most powerful emotion. When he is transformed into an insect, Gregor is made unable to work by circumstances beyond his control. Despite the fact that his metamorphosis is not his fault, however, he is racked by guilt every time that the family mentions money or that he thinks about the pain that he has inadvertently inflicted on them by losing the ability to support them. Guilt, it turns out, is deadly, as Gregor realizes at the end that his life is the only thing keeping the family from a better life. He dies for them just as he lived for them: out of guilt.