I feel like every year, something relatively unimportant gets forgotten and not realised until Christmas Eve once all of the shops are closed.
This year, mine is placemats / coasters that don't look ridiculous with the table cloths. I've just laid the table and debating between no placemats and potentially ruining white table cloth, metal place mats that look absurd, or setting DSD the challenge of turning empty amazon boxes into something "artistic" with the arts and crafts set we got her for tomorrow...
Make me feel better, what did you forget?