- Anvilicious/Some Anvils Need to Be Dropped: "Don't judge people by their appearance." "Don't hide from the truth." "Live up to your own standards before imposing them on everyone else." "If you were wrong, own up to it." "If a girl in your school has third-degree burn scars on her face and hands, and she happens to be wicked smart and articulate, don't piss her off."
- Complete Monster: Virgil Byrnes, the father of the book's title character, is a monstrous abuser who constantly beat his wife and child, attempting to drown the former in the kitchen sink during the one night she fought back. When 3-year-old Sarah walked in, Virgil pressed his little daughter's face onto the top of a red-hot stovetop and held it there until she was disfigured forever. Virgil refuses to let Sarah have her face medically reconstructed, promises her he'll "burn the rest of her" should she ever tell anyone else what happened, and tries to make good on his promise at the end of the story while violently stabbing Sarah's high school friend. The only reason Virgil does what he does is simple; it's his nature.
- Moral Event Horizon:
- Virgil Byrnes may be Chris Crutcher's defining example of an abusive parent (alongside Rich Marshall); it's revealed Sarah's facial scars are a result of him having held her face to a burning hot stove when she was just three years old.
- Mautz crosses this when he attributes Mark's suicide attempt to the other students in Lemry's class.
- Nightmare Fuel: Sarah Byrnes' facial scars. Though how she got them is good for a few sleepless nights, too.
- Virgil stabbing Eric, and then chasing him through town with the knife still in his skin. And Dale having to remove the knife with his bare hands. If you have a weak stomach, do not read that spoiler.
- The Woobie: Eric, Lemry, Ellerby, Jody, Sandy, Carver... This one, 216-page book rivals the entire Harry Potter series as a deep, dark pit of Woobiedom. (And for the record, Harry Potter has a Woobie page to itself.)
YMMV / Staying Fat for Sarah Byrnes