I used to Believe...
This website is so fascinating. It's a collection of childhood beliefs. Some of them are downright hilarious.
I loved this belief:
"I was always told that if the dog was wagging its tail, it was happy and friendly. If the cat is switching its tail, it was agitated and likely to scratch. I tested this explanation by forcing our happy dog's wagging still. It very quickly became unhappy and bit me. Voila! The adults were right. So, naturally, the next step would be to force the cat's switching tail to hold still and it would be happy... the results weren't what I was expecting."