factfinder, try listening to Jose Feliciano Feliz Navidad. I don't know how anyone can hear it and not have at least one corner of his/her mouth turn up.
With holidays, it's all a matter of perspective. Some cultures look for any reason to celebrate and to be festive. It helps life to be worth living to have something to look forward to, regularly. Think about how gray and dismal the long winter months can be. Having monthly celebrations to look forward to gets a lot of us through them. If you don't celebrate Christmas, then celebrate something else that day. In the USA, most of us get the day off. Throw a dinner party for goodness sake.