Factual error: There would not be that many leaves still on trees in December in Grand Rapids, Michigan. The snow looks very fake and sprayed on in some shots.
Other mistake: When "Santa" (Billy Bob Thornton) is in the bar with his mother, the bartender tells him that "smoking is not allowed in here." In the next scene, "Santa" is shown tapping his cigarette on an ashtray. If no smoking, why is there an ashtray?
Continuity mistake: A group of people are in the copying room taking turns taking pictures of their butts on the copier. When one of them sits on the glass part of the copier, the glass part breaks. When he gets up, it's not broken.