and what do you think is the worst?
I'm really looking forward to Christmas Eve usually ~ 6 /7pm when it it is time to settle down to the Snowman and the Snowman and the Snowdog, then putting out "bits" for Santa and his reindeer, reading "A Night Before Christmas" etc etc and of course Christmas morning.
The worst part for me is having to drive hundreds of miles over the Festive season and shelling out money we haven't got on hotel accommodation. I find it really stressful but I do it so the children will see their grandparents/cousins etc as they will never come to us as "they like spending Christmas at home" 
What do you like the most/least?