The dramatic father
Because the father in this novel is missing through the first half of the story, the book draws out this dramatic irony where the family is examined in one setting, without the father, so that when the father arrives, his influence in the home will be crystal clear by comparison. When he finally arrives, he is in a state of manic neurosis, convinced that he has everything under control. He does his own laundry as if to say, "I'm happy and healthy." But when the man arrives to whom Weston owes money, death is shown not to be a respecter of his self-delusion.
Addiction and childhood
This novel explores the way children absorb the twisted personalities that drug abuse and addiction produce in bad parents. The absent father betrays his wife to go on long benders without her, leaving her bitter and desperate without money. The children, because of the dramatic irony of their innocence, are unaware of the influence that narcotics have on their parents' adult lifestyles. They just absorb the personalities and become those people in earnest.
Emma's lost innocence
A young adult might still be in a state of innocence. This is the way the novel invites us to feel toward Emma. We see her acting out, but in the context of her mother and brother's emotional abuse, Emma is easy to empathize with. Then one day she commits a mass murder. The revelation of her true evil is a statement on the irony of abuse. Not only does it damage her emotions, it also has a chronic affect on her character, so that when she finally decides to commit an act of evil, she goes to the most extreme decision possible. She also dies shortly after committing her life to evil.
The housing irony
The parents are as close as they can possibly be to literally rending their home in two. There is a certain point in the book where the couple is only together because they each sold the house to different people without the other person's knowledge or consent. In other words, they are so desperate to get away from each other and their dysfunctional marriage that they accidentally pull too hard and ruin their chances of selling the house. This is a symbolic depiction of what a bad marriage feels like.
The thug
The ultimate irony in the novel incites the climax. Act III starts with Weston putting on a show of sobriety and self-control. His wife sees right through it, a hint to the reader that Weston's behavior should be taken with a grain of salt. Sure enough, the reader learns that he bottomed out and got involved with the wrong people because of his addiction. Now he owes money to a thug named Emerson. Emerson is a chaotic character that emerges from Weston's private life (dramatic irony), and the climax is that the two parents lose their daughter Emma to Emerson's violence.
