When I was surprised my dd had written her letter for Santa and politely said I thought she was getting to old for that sort of thing. The letter was wonderful asking first on behalf of her for 6 year old friend, before a few small gift for herself and lastly "Peace without fighting or conflict".
This then started a very interesting conversation about Santa "Santa is like metaphysical being, this lead to Santa been the message of Christmas to atheist. I will never look a Santa in the same way, does a part of St Nicolas still live on. Meaning a part of us still believes and hence the tradition of the present in the stocking lives on hundreds of years after his death.