WE ALL KNOW this scene. There is a cute, chubby-cheeked toddler in the supermarket shopping cart, which is brimming with diapers, juice, carrots, potatoes, canned tomatoes, milk, eggs, family-size cereal and about three dozen other things that will fuel a family for a week. Wheeling the cart is a tired and slightly harried looking mom (Sorry dads, data show it’s still mostly moms.). They’re third in line at the checkout: Toddler sees chocolate bar. Toddler asks for chocolate bar. Mom says no.

Toddler asks again.
Mom says no again.
Toddler persists.
Intensity and volume increase.
Mom holds the line.
Onlookers start to watch.
This is better than TV.
Mom looks embarrassed.
Mom is getting rattled.
Toddler escalates to screaming.
Mom gives in.
Toddler smiles through tears. Mom sighs with relief. Peace at last. But at what price?

In toddler-think, the child is learning this: “Mom doesn’t listen very well when I ask nicely for something. I have to ask about seven times, and it helps if I scream.” The toddler’s resistance behaviour (i.e., the screaming) has been reinforced, teaching that boundaries are permeable.

The supermarket is not unlike the dinner table. A small child refuses to eat the prepared meal, so parents cook custom food. The dinner table morphs into a restaurant. Once again, the lesson of the permeable boundaries has been taught.

And what about chores? We can nag till the cows come home, but if our children don’t obey, we’re in a pickle. The garbage starts to stink, and the dishes pile up until we give in and do the chore ourselves, teaching our children, again, that boundaries don’t matter.

All three situations — the supermarket, the dinner table and the chore challenge — share a central dynamic. They all look like power struggles, but under the surface, the core parenting issue is: how do we raise children who are responsible, resourceful and flexible people?

The first step is to accept that, when you go head-to-head with a child, you enter an unwinnable battle. Kids can scream louder and longer than you. They can refuse to eat dinner. They can tolerate stinking garbage and piled up dishes. You can’t.

The toddler in the supermarket desperately needs you to say no to the chocolate bar — and stick to it. Even when he or she screams, even (or perhaps most especially) when a small crowd gathers to see if you’ve got the balls for this, your toddler needs you to teach him or her that no means no.

This is powerful parenting because learning to hear and respect no lays the foundation for a built-in internal compass that will help kids to say no when they’re older. It will help them make good choices.

Saying no in the supermarket will teach your child to take no for an answer. Saying no to custom food at the dinner table will result in kids who are flexible eaters.

(Some non-eating might result along the way, but don’t worry. All kids will eat when they’re hungry enough.) Create logical consequences for undone chores, and your children will learn to help out or suffer the consequences. It’s that simple.

That said, none of this is easy. Social workers call it giving yourself “permission to parent.” The older our kids get, the harder it is to give ourselves permission to parent, because parenting often results in our children acting as if they dislike us, and that hurts. But it’s not about us. We need thick skins in order to grow good kids.

The Jesuits used to say: “Give me a child till he is six years old and he is mine forever.” Your child is that malleable. Give your child the gift of no, and you give the world a gift of a person with a strong moral compass.

We need more of them.

Parenting columnist Joanne Kates is the director of Camp Arowhon in Algonquin Park where she teaches 150 staff to parent effectively and acts as “mom” to 300 kids at a time, every summer.