For the non-religious:
Go into a church on a random sunday, and then go into a church on Christmas/Easter. It's fucking packed. That's about the only thing I hate about Christmas: a packed church full of crying children who don't want to be there. ._.
As for saying 'Merry christmas' to other people and them getting offended, who seriously gives a shit? It's no different than saying 'happy hanukkah' or 'happy kwanzaa' or 'happy holidays' or 'how is it going?'. I think some people just like to be bitchy. Noone is anally penetrenating you with a bible, they are just trying to be nice and using a modified version of 'hello'. Get the damn chip off of your shoulder.
XI Wiki


