OK so a bit late with this one. But The Naked Scientist has an interview with Prof Richard Wiseman (University of Hertfordshire and author of Quirkology) on various Christmas themes (including cracker jokes and Christmas cards).
Richard – What we did was ask people to fill out a basic personality questionnaire that told us whether they were an extrovert or an introvert, creative, not creative and so on; and then tell us what type of Christmas card they tended to give … the most traditional cards – the typical religious scenes were associated with people who weren’t quite so emotionally stable as most. This is a level of what’s called neuroticism.
Chris – That’s not good for Christmas, is it? If the religious people are unstable!
Richard – That’s what most of the research shows. Not so much that they’re unstable, rather that they’re anxious about the world. That’s why they come to believe in religion in part because it provides a big comfort blanket for them. Deep down, they’re quite anxious about the world. That fitted in with some previous research.