No Exit!
Interesting. I expected to come to this board and perhaps see at least one reference to the parallels between John-Paul Sartre's short play "No Exit" and this film.
OK, so it's not Hell in the literal sense as meant in the play, but the theme of torture by proxy through the company of others is there, and even mentioned. Also, before the Thanksgiving dinner scene, the dad says, "well, let's get on with it," as the cutscene fades to black. Those same words happen to be the final lines from the play. Though I'm sure there are probably other literary references that could be associated with this film, it almost seems that it most fits as an adaptation of "No Exit" to a film about families during the Holidays. It fits so well.
Of course, the play was a comedy/drama written by a mid-20th century playwright known for being an Existentialist. Instead of random strangers thrown in a room together with the expectation of being "tortured" in the literal sense only to learn that the real torture is to spend the rest of eternity in that same room ... together ... each with conflicting personalities.
No heroes, no villains, only themselves stuck with each other (much like we are stuck with our families, like it or not). I could go on and on with similarities and dissimilarities, but the direct quote from the play made by the father stuck a chord and I had to go back and partially re-read the work (it's only 30 pages or so) only to reach a stronger conclusion. It is obvious that the work of Sartre was a heavy influence on the writers, both thematically and in dialogue.
Interesting observation I thought I'd share from someone who just watched this film for the first time and hadn't read Sartre since college five years ago. This is an interesting take considering the stereotypical "Holiday dysfunctional family movie."