Trivia: Clark Griswold in the attic watching old movies dressed in a woman's turban and gloves to keep warm is not only funny but a reference to the Norma Desmond character from "Sunset Boulevard", who watches her old films to remember her Hollywood glory days.
Trivia: Eddie's son, Rocky, doesn't speak one line in the entire film.
Trivia: When Clark smashes up the decorations when he can't get the lights working, Chevy Chase genuinely broke a finger when he punched Santa, but stayed in character, kicking the decorations instead, and that's the take used in the film.
Trivia: Even though they play mother and son in this film, Diane Ladd (born in 1935) is only eight years older than Chevy Chase (born in 1943).
Trivia: Chris Columbus was the original director and filmed some early shots, but left after meeting Chevy Chase, saying to John Hughes "I can't do it with this guy". He instead directed Home Alone.
Trivia: Johnny Galecki and Juliette Lewis play brother and sister in this film. 30 years later, the two reunited as boyfriend and girlfriend on The Conners for an episode or two.
Chosen answer: Because there was cat food in her jello mould. He's pointing out the absurdity of someone adding cat food to jello.