Mommy tells absurd stories throughout the play. Her character is created from the ridiculous things she says. Her power in the family comes from exaggeration, not reality. Mommy craves immediate satisfaction in all aspects of her life. She is cold, calculating, and cruel, verbally abuses Daddy into submission, and lashes out at her own mother, whom she sees as a drain on the family's finances. Even visitors, including Mrs. Barker, aren't immune to Mommy's abuse. Mommy shows kindness only to the Young Man, who is young, virile, and handsome. She cares only about outward appearances and thinks nothing of the person within.
With the exception of her sharp tongue, Grandma is nothing like her daughter and son-in-law. She came of age when people worked hard to achieve their dreams, and she sees little value in the materialism and social climbing exhibited by her offspring. Though Grandma is dismissed by her family as a "feeble-minded" relic more fit for a nursing home than regular society, she is the mastermind behind the play's resolution, which also allows her to escape the unhappiness of the apartment unnoticed. Unlike the other characters in the play, Grandma can take action to better her circumstances.
Daddy is literally and figuratively emasculated by his sexual dysfunction and Mommy's constant verbal abuse, making him more like a child than an adult. He is a shell of a man, going through the motions of his personal relationships without making any real connection. Daddy's existence boils down to being a source of power for his wife. He is beaten down and depressed and wishes to be anywhere but where he is, yet he isn't willing (or able) to take action to change his circumstances. Daddy's complacency and passivity are to blame for both his perpetual dissatisfaction with life and his role as the family pawn.
Mrs. Barker is said to be engaged in all manner of social causes—the women's club, the Responsible Citizens Activities, and several other social committees. As the head of the women's club, she is the only character with any power over Mommy, yet this power disappears when she enters Mommy and Daddy's home. She doesn't know why Mommy and Daddy summoned her to their apartment, which furthers her feelings of distress.
The Young Man is physically perfect on the outside but completely empty on the inside. His gradual loss of feelings, desires, and empathy corresponds to the physical mutilation of his twin, whom Mommy and Daddy adopted 20 years before. Fully matured into a gorgeous male specimen, he takes the imperfect twin's place in Mommy and Daddy's life.