Merry Christmas, Happy Hanukkah, Happy Ramadan, Blessed Bodhi Day. Wonderful Winter Solstice, Outstanding Omisoka and a Freakin' Fun Festivus Day!
About time people can come out from under their rocks and be excited about celebrating religion rather than feeling an Atheist will lecture them on how their feelings are hurt. I have many stories on this topic growing up in a very diverse Toronto. Here are a couple
I recall years ago in Toronto I was on the public transit late one night and two transit workers were laughing it up on the sparse subway platform. It was near Christmas, maybe the 23rd or 24th and I was wondering what the commotion was about as it was just myself and these two. Anyways, one of the guys was wearing a Santas hat and yells to the other worker "Merry Christmas pal, even though I'm Jewish" and he goes to hug the other employee. The other guy says, "hey a Happy Hanukkah to you too". They were both in a great mood and I couldn't help but smile at this small example of religious unity. Neither of them shy about it and having a laugh.
At a major corporation I worked at, there was a lady who was walking around giving out Christmas Cards, the guy I worked beside was openly Muslim, she handed him a Christmas Card and he sheepishly thanked her, trying to be polite. At the time I wasn't particularly religious, but I said thank you. She then boldly asked me if I believed in God, this is at work! hah.
I was honest and told her, "well, I am a big believer in science (my beliefs have altered since then, but regardless), more Agnostic I suppose, on the fence about God, or certainly a particular God". I was honest though not rude. She looked at me cold faced and said "you are going to hell you know". I looked at her and calmly replied "thanks for making that call on behalf of God". She slithered away. It never impacted our working relationship, nor was I even offended at the entire incident. Looking back in the whole process of life as it unfolds, these are the experiences I rather enjoy, they are certainly at least memorable to the otherwise mundane social interactions.
Bottom line, as far as I am concerned people have to stop taking offense to someone elses beliefs. Noone is forcing you to believe anything, so stop trying to police peoples expressions. Saying "Merry Christmas", "Happy Hanukkah" or "Happy Ramadan" isn't going to convert you, send you to hell or alter your life, no need to be afraid.