I know very well that children learn by example, but there are some times I would rather not be reminded of it.
When my sons were locked firmly in pre-adolescence, I noticed certain words creeping into their vocabulary I didn’t want to hear. Where did they get that stuff? They would say the words then look at meto see how I reacted. I said I didn’t like that language, and they shouldn’t use it in public places, even if the public place was camped in front of the television watching a movie in which the actors used the language I was objecting to.
It went on. It was a test of my authority. It lowered the level of discourse.  
Civilization was at stake.
So I introduced the age-old institution of the potty-mouth jar. Or swear jar. You know what I mean – a jar in the kitchen that someone puts money in every time they break the rule. “It will cost you a quarter every time you use one of those words,” I said.  
My children immediately made me define exactly which words I meant.  “You know what I mean,” I said.
It was shortly after that that I made a startling discovery.
I didn’t realize I used those words, and when I did, I thought I was using those words only in the privacy of my own personal universe. Replacing plumbing fixtures, for instance – you would think that would be a private experience.
Not when you yell really loudly.
Or when I got cut off in traffic.
Or waited on the phone for forty minutes to talk to someone at the Deparment of Motor Vehicles.
“Twenty-five cents, Dad,” my children gleefully announced.
“#%@!!!!#!” I said.
When I realized who was putting the most money in the jar, I cleaned up my act, declared victory, and retreated.

“No more swear jar,” I announced. “You’ve learned your lesson.”
And we all behaved reasonably well until they reached adolescence. Suddenly, it wasn’t language, it was attitude. Somewhere on their way to adulthood, my boys had become the most sarcastic beings on the face of the earth. Nothing escaped their cynical comments.
So I got a glass gallon jar and wrote on its side “Sarcasm Jar – 25 cents”
I introduced it at dinnertime.
“This will stop your sarcasm,” I said. “I’m serious. Every time someone’s sarcastic, they owe a quarter.”
“Dad,” my older son said, sincerity plastered across his face, “we’re not sarcastic.”
“Yeah, right,” I said.
“Twenty-five cents, Dad!” my younger son.
“That’s not fair!” I said. “You’re trying to make me sarcastic.”
“Dad, we would never do that,” the younger one said.
“Oh, sure!” I said.
“Twenty-five cents more!” the older one said.
They were both in hysterics.
“Forget the sarcasm jar,” I said. “I hope you learned your lesson.”
“We learned from the best, Dad,” they both said.
Like I said, there’s some things of which I don’t want to be reminded. Like that my sons are smarter than me.