Well like I said, it was based off of a stupid Christmas song. Maybe the movie tried to be stupid on purpose to mock the song? But yeah, the kids' eyes do look like the eyes of a serial killer, probably result of the cheap animation. The song sequences were really random, pointless & really stupid. I'm not sure which one is the stupidest: the fruitcake, Grandpa's song or Grandpa's Gonna Sue the Pants Off of Santa.
I also liked when he joked about the tree looking like a penis and that just hurts when the ornaments pop out.