Four Christmases (2008)

Continuity mistake: During the scenes at her Mother's house, Kate's hair goes from blonde to REALLY blonde.

Factual error: Breast pumps need a tight seal in order to work and would NOT stick to Kate's sweater as seen.

Factual error: When Brad and Kate are in the taxi on the way to the airport, they are shown crossing the Golden Gate Bridge. They supposedly live in the city of San Francisco itself, and therefore should be heading south to the airport. The Golden Gate Bridge is to the north, and is completely in the opposite direction, by about 18 miles.

Trivia: Executive Producer Peter Billingsly has a cameo as the ticket agent at the airport. Peter also played Ralphie Parker in the 1983 movie favorite A Christmas Story.

Trivia: Reese Witherspoon and Vince Vaughn reportedly didn't get along at all during filming, allegedly due to their very different approaches - Witherspoon wanted to rehearse everything thoroughly while Vaughn wanted to improvise more. Reese Witherspoon ending up refusing to film a sex scene with him as a result of tension between them.

Trivia: Vince Vaughn's father has a cameo during the Christmas play, sitting behind Reese Witherspoon.

Howard: Your grandmother's boyfriend is a first-class ass sniffer! And you can tell him that I said so.

Howard: Boys, I don't want to speak ill of your mother on Christmas, but she's nothing but a common street whore.

Kate: Cassie! That marker in your mouth, I peed on it.