Natasha Lyonne gives a good performanec and her character is mostly likable, a breath of fresh air in this mean-spirited black comedy about horrible people. But I don't think the movie truly understands what a hideous monster her sister played by Judy Greer is. The movie gets that she's a bad person ...but I don't think it realizes just how bad!
Addicted to Fresno also gets negative points for completely wasting Aubrey Plaza. Delete her from this movie and almost nothing changes - that's a sin!