The turkey will not thaw out on time, even if you take it out of the freezer in November.
No matter how carefully you check the lights before they are put up, the one bulb just out of reach even with the extension ladder, will be broken when you turn them on.
You will always find one gift left under the tree after everyone has gone home, and it will be the carefully chosen one for your rich, childless, bachelor uncle (or spinster aunt) who is over ninety and sickly.
The cards which arrive in the last post before Christmas Day will all be from people you haven’t sent a card too.
Have a merry Christmas anyway!