The conversation goes something like this:

"Please don't wear your hat like that," the parent grumps. "People will get a bad impression."

"I don't care what people think," the teenager shoots back, "especially if they aren't going to bother to get to know me."

"You should care that they'll take one look and think you're something you aren't," the parent tries to reason.

"But you've always told us not to judge a book by its cover," Mr. Smartypants one-ups again.

"Rightly or wrongly, people do make judgments," you sigh. "That's the way life is. You've got to recognize that and try to live with it."

And then you feel bad, not just for reinforcing life's unfairness but for having to teach your kids that reality often contradicts principle.

Welcome to life with teenagers, that time when you get your words thrown back at you, get accused of hypocrisy and find yourself searching for Ward Cleaver wisdom in a world that June never imagined. (And we aren't even to driving yet.)

Even promoting the golden rule isn't always simple. You want your kids to believe that people are basically good and decent. And then you go to a sporting event and see teenagers innocently leaving their gear bags on bleacher seats. When I try to convey the concept of easy prey, my kids are certain that I'm paranoid and overprotective.

A couple of years ago, when my daughter's cell phone got swiped, I jumped all over her for leaving it in an open purse, inside an open gym locker while she retrieved some clothes. "But you ought to be able to trust your teammates," she cried.

And how could I tell her she was wrong?

How do you teach that trust is one thing — a very good thing — but that obliviousness to lurking dangers is quite another?

We insist that our kids work hard because effort and merit will get them ahead. And then they discover on group school projects that there are slackers whose share of the work others have to pick up.

You could tell them it's different in the real world, but that would mean Dilbert had run out of material. And they need to know, don't they, that what you know is valuable but whom you know could prove priceless?

My teenagers resort to the "conflicting signals" defense when they feel stifled by my efforts to shepherd them through the minefields of adolescence.

When I recently objected to an expensive purchase that my son wanted to make, he parried with: "You tell me to act more mature. You say I need to take responsibility. But you won't let me decide how to spend my own money." Or words to that effect.

It's eerie how I channeled my own parents in response: "You don't get to make those kinds of decisions alone. You're still a minor, and I'm still in charge."

It's in the parental job description, you know, that you must check their seat belts, annoy them with checklists, consult with their friends' parents and repeat phrases you swore you'd never use.

I actually felt somewhat better about this after reading about growth spurts in teenage brains.

"It's the adolescent's job to keep pushing the boundaries. It's the parent's job to make sure those boundaries don't put a child in a place that is dangerous," said Andrew Brickman, a clinical researcher in Florida, in a piece by Jodi Mailander Farrell of the Miami Herald.

So you muddle through, trying to nurture their independence and individuality but making them comply with the dress code, play by the rules and appreciate the place of conformity in a free society.

You discuss (more often than they want to hear about it) how foolish short-term choices such as underage drinking, teenage sex, illegal drug use and text-messaging while driving can ruin long-term happiness.

And you trust — yes, trust — that they'll make sound choices even when you aren't hovering nearby.

Linda P. Campbell is a columnist and editorial writer for the Fort Worth (Texas)Star-Telegram.