What makes the characters even better are the amazing actors portraying them.
The movie never really goes out of its way to tell the viewer something about the characters and instead lets it happen naturally throughout its runtime. The exposition necessary to set up these characters is masterfully woven into the dialogue. Characters are extremely well defined and never seem to say or make any decisions which one could consider inconsistent with their usual behavior. That is not to say that this movie is as mundane as possible since the manner the story is presented in is anything but generic. The concept of a mother struggling with a troublesome child is not all that unique, and even though this movie has quite a few interesting story elements up its sleeve, at its core it still is a film about a dysfunctional family that has been told many times before. Right from the start this unique family seems to be heading into a disaster but things change when a mysterious neighbour inserts herself into the lives of Diana and Steve. Immediately Diane is presented with the option to send Steve away, but his undying love for his mother paired with her own stubbornness and pride stops her from making such a drastic decision. One of the movies main characters Diane Després finds herself in exactly that situation when her son Steve who has ADHD gets out of a youth detention center. The movie 'Mommy' written and directed by Xavier Dolan takes place in an alternate version of Canada where any parent has the option to rid themselves of their troublesome children by sending them to an institution. Kyla may find that she needs the Després as much as they need her. Kyla is a high school teacher on sabbatical as she deals with her own emotional issues, which are manifested in stuttering whenever she feels incapable of dealing with her life.
The second and more important is Kyla, who lives across the street with her husband Patrick and their adolescent daughter, they who are in transit in their life to wherever Patrick's job will take them. The first is Paul, a lawyer, who does have that sexual interest in Die as he tries to help Steve through his legal problems. Their lives, both individually and as a family, are affected with the entrance of two of their neighbors. Despite they always yelling expletives at each other and Steve sometimes demonstrating those violent tendencies toward her, Die and Steve truly do love each other, his emotions which are sometimes manifested as an Oedipus complex especially as he seems to need her complete attention most specifically when it is being directed at possible male suitors. However, with this deinstitutionalization, she has to take care of him which means only being able to do home based work.
She made this decision to deinstitutionalize him as she didn't like the alternative, sending him into more restrictive juvenile detention from which he would probably never be rehabilitated. He was just kicked out of the latest in a long line of facilities for setting fire to the cafeteria, in turn injuring another boy. She institutionalized him shortly following her husband's death due to Steve's attention deficit hyperactivity disorder (ADHD) and his violent outbursts. That bread-winning ability is affected when she makes the decision to remove her only offspring, fifteen year old Steve Després, from her previously imposed institutionalization, one step below juvenile detention. Considered white trash by many, Die does whatever she needs, including strutting her body in front of male employers who will look, to make an honest living. Forty-six year old Diane Després - "Die" - has been widowed for three years.