I like “Merry Christmas”, but to be honest, I prefer the ancient Christian name and greeting for this holiday.
When Christians greet each other on or after the Feast of the Nativity of Christ, during the Feast period (ends January 5 this year), one says:
“Christ is born!”
and the other answers:
“Glorify him!”
The term “Christmas” is a contraction of two words “Christ Mass” which is a local term to the Church at Rome. “Merry Christmas” seems to have no connection to the Christian faith. Maybe “Merry Christmas” originated in England or something.
Before the Feast, which is December 25 on the new calendar, Christians do not greet each other in any special way, as the 40 days before the feast day are a Lenten period of fasting and preparation.