The Christmas carols over loudspeakers and "Merry Christmas" wishes have already started, despite the fact that Thanksgiving hasn't happened yet. More time to buy stuff in, I suppose. Regardless, I think that the constant assumptions that Christmas carols and "Merry Christmas" are appropriate for public - and especially business - spaces are selfish assumptions.
It is utterly and completely presuming that everyone else is the same as you, that everyone celebrates Christmas the same way, or that they celebrate Christmas at all. It ultimately ends up being a self-serving gesture, a selfish gesture.
And one that communicates how little value everyone else has.
Perhaps it would be different if other religion's holidays (and atheist ones as well) were celebrated as openly and publicly. Instead, it demonstrates what "normal" is supposed to be, which actively devalues everyone else. Imagine, for a second, that you were the only meat-eater around, and you kept getting served tofurkey? At what point would you start to think that maybe they just didn't give a damn about you?
When speaking to people at your church, or people that you *know* are Christians, then saying "Merry Christmas" is wishing *them* well. Wishing a Merry Christmas upon everyone - thinking it unimportant what their faith or lack thereof is - is serving only yourself.
Happy holidays, everyone.
(Oh, and the season that starts next week? That's ADVENT. The Christmas season is from 25 December until 6 January - the twelve days of Christmas. If you insist on wishing your religion's holidays on other people, at least get it right.)