We'd generally scoff at a sentiment like, 'Well, you're not being stalked by a serial killer in your attic, so it must be a Merry Christmas,' but does hold true in this case. We'd usually recommend setting the bar a bit higher if you're thinking of entertaining over the holidays, but we've been to some mixers that challenged even that assertion.
Black Christmas was one of the first films that helped spawn the 'slasher' genre of horror movies, pitting a college sorority against a mysterious killer (calling from inside the house!) on Christmas Eve. Alcoholism and odd feline imagery abound alongside Christmas lights, but the violence was strong enough to establish it as a cult-classic.
No matter how bad a holiday party might get, or how trying a dinner guest may turn out to be, we just pop this one in, and be glad they aren't trying to kill us. Sure, it makes us jump out of our seats and start swinging a butcher knife every time the doorbell rings...but those carolers should have known better.