I always call christmas "Capitalism Day", it's not even the season Jesus Christ was supposedly born in (late spring-mid summer).
In the 1800's Coke Cola changed Santa Claus' suit from green, the original elf color, to red as a marketing campaign. And just like every other federal holiday, you stuff yourself of meat, beer, and butter steadily eroding away your health, buy shit you don't need or want with money you don't have, and talk to people you don't like.
Greed, Gluttony, Envy, Lust, Sloth, and Pride; Christmas the most "sinful" day of the year. The irony is lost on most, but I do enjoy the aesthetic if nothing else.