It's a Christmas song about Christmas songs not being what they once were.
"These songs brought us together, good time memories forever, now I
know what they mean and what they've given to me I would never believe
— we'll be singing them over and over and over again, every December
they get in our heads." We suppose it's a lot like a festive version Morris Minor & The Majors' PWL satire 'This Is The Chorus'.
Sleigh bells, brass section, false end, etc etc.
The single's out the same week as the X Factor winner so we guess this'll be the 'alternative' (ie released by Universal, the world's biggest music company) release.
Should have been called 'The Christmas Song'.
We're going to the pub.