For many little children, Christmastime is a particularly joyful one - think presents, fairy lights, delicious food, crackers, paper hats, and lots of fun with the family.
Which means that, in the run up to the big day, they CAN find themselves getting a little over-excited and start misbehaving.
And this can, as many parents know already, lead to the kids finding themselves on Santa's naughty list.
Redditor sgtpnkks uploaded a pic of this letter from 'Santa' that his sister used to get her daughter to behave.
It reads:
Dear Lydia
I am sending this letter to let you know that as of right now you are on the NAUGHTY list.
You have 10 days to straighten up and behave to try and get back on the NICE list.
This means no smacking your sister, or talking back to your parents, you also need to clean your room.
I will be watching and getting reports from your parents.
I had them give me access to the cameras in the house so I can keep a better watch.
I'm watching,
Santa Claus
It's genius, sure, but more than a little alarming - and some have expressed concern that it could cause the little girl in question to become afraid of the all-seeing Father Christmas.
It certainly adds a new terror to the Christmas song lyrics: "He sees you when you're sleeping, he knows when you're awake. He knows if you've been good or bad - so be good, for goodness sake."
You better watch out, Lydia.