Never. What I do find strange is when people ask me if I celebrate Christmas before wishing me a "Merry Christmas." It's like they are both asking me if I'm Christian and if I take offense easily.

As an Atheist I like to think of this time year as a secular time to give back and spend time with family. So call me a hypocrite but I still "celebrate" Christmas and give my kids gifts because lets face it most american kids do and I don't want my child to be left out of the fun.