Cusack, who plays Sheila, explained that the family members are not particularly worried about their lifestyle.
"If you live your life feeling bad about your circumstances, it is hard to move forward," she told TV & Satellite Week.
"The idea of this show is that the Gallaghers are not feeling guilty about how they live. That is so awesome to me."
Cusack also suggested that viewers may be able to relate to Sheila, saying: "She is an extreme version of anyone who doesn't feel like going out or socialising or would rather not deal with things. Other people may be more extrovert or introvert, but she is probably not that far removed from what a lot of us experience."
Cusack has previously described her role on Shameless as "a gift" and explained that she likes the fact that it is different from other shows.
Shameless has already been renewed for a second season by Showtime. The first season is currently airing in the UK on Thursdays at 10pm on More4.
Watch our recent interview with Shameless star William H Macy below: