Goofs

When Kat arrives back at the house, she leaves her car parked in front of the carport. When Elissa, Sam and Kat return a few minutes later to switch off the Christmas lights, there is no sign of the car.

After Kat pours E.B. a drink before the proposal, she passes an empty glass to E.B., only for the drink to be present in the next shot when E.B. gulps it down.

After Kat turns on the shower over Sam in the bathtub his clothes are drenched. As they continue the conversation his shirt goes from slightly wet to dry between shots.

After Sam and Kat go outside to dance, the second couple who follow them outside are still sitting at the table when Tom asks Elissa to dance.

When the main characters meet for the first time, and are coloring under the table, Kat uses her left hand. In scenes from future Christmases, she's right handed.

When Sam looks at a picture of Kat being sick on his cell phone, he is using a flip-phone. Then, when he is shown looking at his phone, he is clearly holding a Nokia phone that is not a Clamshell style and is incapable of sending or receiving pictures.