I come from Yorkshire and when we would sing Jingle Bells at Christmas I thought 'a one hose open sleigh' was 'a one horse serpent sleigh' because of the strong accents. I spent most of my childhood thinking that Father Christmas road a dragon.
A childhood belief about hymns

others believed things like this
- I used to think the song "Walk this way" by Arosmith went horse and sleigh insted of singing walk this way.— Derek
- I was told that for every christmas carol i sang before christmas time santa would give me one less present!— K
- Do you really mean to tell me that father Christmas is a myth?
Finally......— Peter (Aged 70) - When i was child, i used to think my father was my father christmas.— BeB's
- I used to think that Father Christmas stole toys from Smyths.— Shovel Tem
- We didn't have a chimney in our house. Father Christmas had to come in through the letter box.— Ginnean