Parental fibs
It's sometimes easier to make up a wild story, rather than explaining the truth to kids, because the truth is either unpleasant, complicated, or something the child doesn't care about. Sometimes the parental lies are simply a way to get children to do as they're told.
One daughter recalls her mother telling her that going out with wet hair, wearing fashionable cropped clothing that didn't come right down to your bum and sitting down on cold concrete all cause a mysterious illness known as a "chill on your kidneys".
"When questioned on the symptoms when I was an adult, mum still said 'well you'll know all about it when you catch one'. It seems to also be caused by inadequate vegetable consumption and staying out late without your good coat."