" The lesson applies as well to the politics of family as country. The parent who grants privileges or enforces rules erratically invites rebelliousness by unwittingly establishing freedoms for the child. The parent who only sometimes prohibits between-meal sweets may create for the child the freedom to have such snacks. At that point, enforcing the rule becomes a much more difficult and explosive matter because the child is no longer merely lacking a never-possessed right but is losing an established one. "

― Robert B. Cialdini , Influence: The Psychology of Persuasion