I am now reading Talk to the Hand, The Utter Bloody Rudeness of the World Today, or Six Good Reasons to Stay Home and Bolt the Door by our beloved Queen of Apostrophe, Lynne Truss. She states in her intro:
Once you leave behind such class concerns as how to balance peas on the back of a fork, all the important rules surely boil down to one: remember you are with other people, show some consideration.
I think permissive parents forget this basic rule in an effort to not squash their darlings' potential, forgetting that the rule teaches each of us about "I and Them." The little darlings instead learn that "I rules Them. Yes, I am not a parent myself but I've taken care of neighbors' children who had the rude awakening when under my care. It has been rather funny to get reports from parents about the children behaving themselves when with me.