Our priest and servants certainly discourage us from celebrating Dec 25 as Christmas. My priest offered us an absolution to break fast on Dec 25. since I was raised Protestant, and he did not want us to offend my family by not eating with them. We told him it was ok though because we take seyyami food and they are not offended. We exchange gifts with my parents and brother on Dec 25, but certainly not with each other. There is nothing dogmatic about the date, it's just the same date on a different calendar... But if we are immersed in our tradition then we will not feel at all that it is Christmas on Dec 25, we will feel that the end of advent is approaching, with just one or two more Sundays of Koiak praise left to attend before the Feast. When we go to my parents it feels like a family event like a birthday or anything else. When Jan 7 comes and we attend the vigil, then it is Nativity. I didn't even realize that this weekend was their Christmas until my parents called to work out what time we were coming. There is certainly no santa clause in our house. If possible, we celebrate St. Nicholas' feast by attending Liturgy. One year my priest announced it by saying "and on Wed. we have Liturgy from 11:30-1 for the Feast of St. Nicholas, whom the Americans have turned into a big fat clown".
It is sad when Orthodox are more concerned with celebrating a feast of materialism than the feast of the Nativity. It is also sad that everyone comes for the feast of the Nativity, the 3rd most important feast on the calendar... But less than half as many come for Theophany, the second most important feast. It seems strange to me when Orthodox (old calendar) say "Merry Christmas" to each other, almost from the start of December now, like the world. Would we say "Khristos Anesti!" two weeks before the Resurrection, in the middle of Lent and Pascha week? Then why do we say "Marry Christmas" during the advent fast? Even in the west there used to be Advent, and then Christmas. Now the fasting of advent has been replaced by chocolate calendars, and instead of 12 days of Christmas building up to the greater feast of Theophany, we have a month of materialistic Christmas followed by 1 semi-religious day, that is immediately forgotten for the greater feast of boxing day when everything is on sale at the stores...
I have no problem wishing Catholics, Protestants, and new-Calendarists a merry christmas on their feast, and thanking them if they wish me the same... but I have no feeling that that day is anything to me. There is no please for celebrating it as the American feast of materialism while we're in the middle of the advent fast, preparing to celebrate the mystery of the Incarnation.