It's difficult for me to say as well. Just the other day, a co-worker said "Merry Christmas" to me and I instinctively said "Thanks!" Then she paused and said, "Well...you know, IF you celebrate Christmas. If you don't, I'm not trying to force it on you." And I just laughed and said "Of course I celebrate Christmas." I guess she noticed my hesitation and was wondering why I didn't say it back. LOL