Going down this rabbit hole, and acknowledging the intense satisfaction I got from these little revenge fantasies against 7-year-olds, got me thinking about the parameters of acceptable maternal behavior. Surely I was not the first mother to have had these thoughts, but I couldn’t recall many instances of people discussing this kind of rage openly — not actual mothers, and not fictional mothers, either.

It struck me that as enlightened as we are about some of the gray areas of human nature, other gray areas seem inherently off limits. We are uncomfortable with mothers who are not easily definable, with good mothers who sometimes think bad thoughts and even do bad things.

In the movies, if a mother is going to be bad, then we want her to be really bad — Texas Cheerleader Mom bad, Joan Crawford wire-hanger bad. Otherwise, we prefer fictional mothers to be gently flawed and efficiently redeemable. We want their mistakes to be caused by misunderstandings, their shortcomings the result of a lack of confidence, like bringing store-bought cookies to the potluck and trying to pass them off as home baked.

In fiction, wackiness is valued above all in the flawed mother, because pain caused by the wacky mother is not real pain; it’s amusing, sitcom pain, and as such does not last beyond the episode and leaves no scars on its victims.

I think that essentially the same is true in real life. We are uncomfortable with mothers thinking horrible things, even under horrible circumstances. We don’t want them to be cruel unless the cruelty is directed at someone who clearly deserves it. We are unnerved by maternal ugliness and malice and selfishness that can’t be entirely justified or — even worse — satisfyingly resolved.

We don’t want mothers to throw balls at children’s heads, but we especially don’t want mothers to want to throw a second ball, for punishment, after the threat has passed. My maternal instinct to protect my child in that swimming pool is forgivable; my maternal instinct for vengeance is not. At all.