"If you don't behave yourself, you won't get any candy". We are used to making such an insignificant thing as is candy our ally in our parenting duties. And we don't usually take into account that, as good a babysitter candy can be, it's not the most reliable of assistants. If we automatically use them as an object for blackmailing instead of facing conflict with our children, as it happens in the tale, one day they could run to the Realm of Candy and never come back.
