It's about having the things that you wouldn't normally indulge in or aren't available at other times of year.
I love nuts, but at Christmas we have a bowl full of all different kinds and a nut cracker.
We only have a punch at Christmas....or maybe New Years Eve.
We only have mince pies and Christmas pud with brandy butter or cream at Christmas.
My mum always likes to put on a small feast on Christmas eve and Boxing day. She makes her own sausage rolls and a very heavily laden sherry trifle and we wash it down with wine or other alcohol, crisps and dips, sandwiches and maybe a mince pie warmed up with clotted cream.
It's tradition in our family. A couple of us always take the kids out for a very very long walk on the beach to tire them out. Take them home and we all get stuck in with preparing the veg for the next day whilst having a tipple. We feed the kids whatever they want (normally a Mc D's as a treat), bath them and then bed. Mum prepares the tea feast whilst the rest of the adults sort out last minute wrapping, whilst having more tipples. Then after we've eaten and put all the pressies under the tree we normally have a game of something.....whilst having a tipple.
It's only a couple of days a year and we love it. We have other family traditions too such as the youngest kids help to hand presents out and reading the gift tags. Or on Crimbo's eve at midnight, we all open one present each, chosen by someone else. Only a small present normally out of the stocking. This is due to the family being part German, as it's traditional in Germany to open presents on Xmas eve.