Merry Christmas etiquette

Christians are celebrating the birth of Jesus Christ today. The celebration is called "Christmas". It is (ideally) an uplifting time of joy, gift giving and family. If you want to be cheerful and polite to Christians, it's appropriate to say "Merry Christmas!" to them. In many Christian societies (e.g. the U.S. outside of San Francisco), it's an appropriate greeting to strangers. They are most likely either actual or ethnic Christians. If not, they're likely to be good natured about the greeting, recognizing they live in a Christian society and respecting that. In a few cases, you will come across an anti-Christian bigot who will reject your good cheer. Do not be concerned about their reaction. Unfortunately, there will always be a few intolerant folks in the crowd. btw, don't say "Happy Holidays." If you believe in Holy Days, just say Merry Christmas. If you don't, say "Hello".