Corrected entry: At the beginning the Grinch is looking down on Whoville and drumming all his fingers. But when it cuts to another angle, he's suddenly only tapping one of them.
Correction: It doesn't take a minute to go from drumming all fingers to just tapping one of them. They wouldn't need to change scenes for that.
Corrected entry: At the end of the story the Grinch has blue eyes except for one shot - when he becomes shocked seeing the sled full of Christmas things begin to slide off the mountain - where they're momentarily red again.
Correction: This is not a mistake, it is done deliberately. It could be because of the stress/shock of losing the sleigh.
Corrected entry: The Grinch has red eyes until he has a change of heart. Then they turn blue and remain that way for the rest of the story.
Correction: This isn't trivia, but one of the main plot points showing the Grinch's change of heart.