To a certain extent, as one of my friends pointed out, this is just because we live in an informal culture, and it is hard to be informal and serious. I think there is a lot of truth in that. After all, when we want to do really serious things in life - I have in mind the big occasions, like getting married, or burying someone - we still reach for formality. It wouldn't seem right to mark those huge things with an informal tone. Seriousness does demand a certain level of formality. Isn't it a shame we don't consider meeting with God's people for worship to be serious in this way?
I wonder though - if we don't know how to be informal and serious, perhaps it is a bigger problem that we don't know how to be joyful and serious. In fact, there is no 'perhaps' about it: this is a bigger problem. Informality is a cultural preference; joy is a gospel command. It is interesting that as I was thinking about this I had an encounter with Father Christmas - not in the flesh, which would be odd and also unseasonal, but in The Lion, the Witch and the Wardrobe, which I'm currently reading with the boy. Here's Lewis:
"Some of the pictures of Father Christmas in our world make him look only funny and jolly. But now that the children actually stood looking at him they didn't find it quite like that. He was so big, and so glad, and so real, that they all became quite still. They felt very glad, but also solemn."
And this bit:
"Lucy felt running through her that deep shiver of gladness which you only get if you are being solemn and still."
Perhaps there is something we could learn from Santa...