No I am not afraid of offending someone saying, "Merry Christmas" since I am not offended if my Jewish neighbor down the street chooses to wish me a Happy Hanukkah or someone else in my travels says, "Happy Festivus for the rest of us," and if I was I would need to seriously get over myself. A really funny comedian Brad Stine made a very good point the people who primarily don't say or are offended by Merry Christmas are those who don't believe in God or the birth of Jesus. Therefore it really makes no sense if you are offended by something you don't believe in, so as Brad says, "PUT A HELMET ON!"
I have heard all the arguments...it's not His REAL birth date, how can you believe a baby was born of a virgin, Horus was really born on December 25th blah blah blah. I won't knock your spiritual beliefs so hows about you don't knock mine. I am willing to share with you what I feel, and believe deep in my heart and soul, but I am not going to tell you you are wrong and then proceed to list your shortcomings.
So when someone says to you, "Merry Christmas" don't grumble and growl if that is your usual SOP smile because someone cared enough to share their joy with you.
Merry Christmas to All.