At the moment Seven is running repeats of repeats of Kath & Kim on a Saturday night. Years and multiple viewings later, the series still draws almost as many viewers as The Footy Show (and more than NAB Cup grand final). And even when the foxy ladies from Fountain Gate finally retire from our screens you can bet that their legacy will live on with the one-liners and catchphrases they've bequeathed us. How many of us now sit down with a nice glass of "kardonnay" at the end of the day? Or relish any pleasurable object or experience as "noice, different, unusual"? Or demand that our friends, partners, colleagues, offspring "look at moi"?

Like any cliche or aphorism that has stood the test of time, TV catchphrases serve a purpose. Sometimes it's quite a profound purpose. A neat line from a satire or spoof can capture the human condition in a few memorable words. Seinfeld's "Yada yada yada" perfectly expressed our bone-deep fatigue with a world chock full of BS. Or consider the pithy insight of: "Computer says no". Confucius himself couldn't have done better in expressing our maddening helplessness in a technology-driven world. Sometimes that purpose is less profound, but just as important. The mantras of reality and game shows, for instance, provide everyone with a way to be mean and dismissive, while pretending to be funny and light-hearted. "You are the weakest link. Goodbye." "The tribe has spoken." Crucially, TV catchphrases give geeks and social misfits borrowed wit. When we do something dumb, we have the opportunity to instantly lean on the TV geeks and social misfits who have gone before and provided charming verbal defusers. Obviously, Maxwell Smart is our king. "Would you believe ...?" or "Missed it by that much" smooth over all kinds of physical and verbal trips and pratfalls. Meanwhile, Sergeant Schultz provides that handy catchall - "I know nuh-think" - beloved of politicians, corporate moguls and mere mortals alike.

TV catchphrases are, of course, cultural touchstones too, a way of identifying whether you are one of us. In his book Cad: Confessions of a Toxic Bachelor, Rick Marin describes tumbling into bed with a woman and spying an enormous jar of lubricant on the nightstand. "That's the second biggest jar of ... I've ever seen," he says. When his paramour inquires gravely about the largest jar he's ever seen, he knows he's with the wrong girl. Some have an even clubbier feel. If you described yourself as being "Auf'd", who would know what you mean? Other fans of the original Project Runway, of course. When Heidi Klum gives eliminated contestants the double air kiss, she always accompanies it with a fond but stern "Auf Wiedersehen". When someone gravely intones "Make it so", only dedicated Trekkies recognise it as a pet phrase of Captain Picard. And if you inform someone they're "entering another dimension", you're both showing your age, and identifying yourself as a hard-core Rod Serling fan.

Of course, nothing's more annoying than people whose entire conversation comprises lines from Little Britain. But catchphrases are a great way of livening up ordinary conversation. Why say "Dinner's on the table," when you could say "Come on down!" Or, "Did you call me?" when you could say "You rang?" They're a wonderful, enduring shorthand that encapsulate a moment or a state of mind, trail a bit of the fun, frivolous spirit of telly in their wake, and link us to our peers. They do what television does best - and even great art rarely achieves. They unite us. QUOTE ME

Few television series have so many memorable and oft-quoted lines as The Simpsons. Of course, being on air for 20 years doesn't hurt. But there's something about the yellow family from Springfield that has utterly captured the zeitgeist. Bart's "Bite me!" has become the bane of mothers of primary school boys throughout the Western world. But the real evidence of the ubiquity of its catchphrases - and its cultural influence - must be in the fact that two of its tropes have entered not just the popular lexicon but actual dictionaries.

You can now find "Meh..." in the standard Collins English Dictionary, and "Doh!" in the Oxford.