It happens each time one of my children enters the teenage years (sometimes a little bit before). I go from having a lovely child and feeling like a reasonably pleasant parent to having a moody houseguest and becoming a shrew.

You’d think, having gone through this now four times, that I’d figure out how to avoid it. Or that I’d expect it. Or not let it bother me so much. Nope. It happened again, it caught me off guard, and I hate it.

To be fair, it’s only natural to be optimistic each time a child of yours moves out of the sweet years. After all, they are such sweet years: the years after diapers and being woken all night, the years when you begin to have real conversations and real fun with them, when they make you laugh and still love to snuggle with you. Sure, they can be messy and maddening, but overall they are so sweet that you think: how bad could the teenage years be?

Pretty bad, of course. Not just because of how teens act, but also because of how we parents end up acting in response. Here’s why turning into a shrew is inevitable:

Teenagers are really annoying. I’ll walk into my 15-year-old’s room with every intention of having a pleasant conversation … and see half of the cups and mugs we own on every surface, half-eaten food on plates balanced on top of piles of dirty laundry, and garbage everywhere else. Poof! I turn into a shrew. Whatever I might have been planning to say turns into yelling at her to clean up. Whether it’s making me late (there’s always something that is forgotten, and getting dressed takes longer starting at age 12), not listening to me about bedtimes (or other previously unchallenged house rules), or snarling every time she is asked to do something like walk the dogs (she acts as if I’ve asked her to do our taxes, fix the furnace and change all the tires on the car) … time and time again, my intention to be patient and loving gets shredded, and I become Shrew Mom.

Teenagers are not always completely truthful. Maybe yours are. And it’s not like mine lie constantly. But sometimes the homework isn’t done when you’re told it was, sometimes the test actually was handed back, sometimes the after-school (or evening) destination is a bit different than you’d agreed to, sometimes that thing they said they didn’t borrow shows up in their room … In the 12 years since I started having teenagers, I’ve learned that things are not always exactly as they are presented. Which makes me prone to second-guessing and nagging … another way I become Shrew Mom.

Teenagers don’t always see things the way we do. We want our children to see the world the way we do; We want them to share our beliefs and values (and perhaps our party affiliation). Even more than that, we have such hopes and expectations for them. We think it would be totally awesome if they studied hard all the time, excelled in sports, did plenty of interesting extracurricular activities, got a job and were consistently polite and helpful. Not only do we think that this is good for them right now; we see it all as leading to a good future for them. When our teens fall short, or don’t even show interest in meeting expectations, it makes us frustrated and worried. We nag, we push, we fight … we turn into shrews.

Besides the fact that our expectations are sometimes unrealistic, there’s the fact that for teens, meeting our expectations isn’t at the top of their priority list. Peers are more important than we are. They think we don’t understand. They think they are the ones who should be making decisions about their lives, not us.

And they are right.

I don’t like being a Shrew Mom. It makes me feel bad about myself, and doesn’t exactly do great things for my relationships with my kids, either. Some of it just has to be endured, to keep them out of bad trouble (and limit the ants in the house). Total shrewdom, though, shouldn’t happen. It’s either a sign that it’s time to get professional help — or that it’s time to let go of what we are trying to make our kids do or be.

That’s the thing: Adolescence is when our kids begin to separate from us, as they need to do. And just like God made babies and little kids cute, so we don’t leave them on a doorstep somewhere when they keep us up all night, throw tantrums and otherwise screw up our lives, I think God made teenagers hard so that we can let them go.

Our teens don’t turn us into shrews to make us crazy, as much as it feels that way. They turn us into shrews so that they can grow up and away… and turn into shrews with their own kids someday.

Which will be fun to watch. And make us feel so much better.

Claire McCarthy is a pediatrician. She blogs at the Huffington Post, where this article originally appeared, and at Boston.com as MD Mama.

Image credit: Shutterstock.com