As everybody knows, unless your just not payign attention, most parents tell lies to their children as a tactic to change their behaviour. Often in my case it did not work, but it was a popular practice in my childhood. A study of families in the United States and China indicates that this practice is an international constant and may have long-term effect on behavioral development. Oddly, the most frequent example related to parents threatening to leave children alone in public unless they behaved in socially acceptibole ways. “I’m goign to leave you little Jimmy!!!” (Oh the KMart memories!)

Persuasion ranged from invoking the support of the tooth fairy to telling children they would go blind unless they ate particular vegetables.
Another strategic example was: “That was beautiful piano playing.”

Read more on the BBC’s website: Most Parent’s Lie to Their Children.