Two decades later we are sitting in Groening's office in a quiet corner of the 20th Century Fox lot in Los Angeles, the scene of the crime as it were.

"Let me tell you about that show," he says, kindly thinking he somehow needs to set the record straight. "I studied Australian culture and history to make sure we got it right and then the writers said, no, no, we're going to go out of our way to get everything wrong.

"I said at the time, I don't think that's a good strategy," he adds.

Unlike the Brazilians (who took great offence when the Simpson family visited Rio and encountered all manner of stereotypes), Australians were, by and large, not offended by Bart vs. Australia with its clockwise-draining toilet gags.

Enough time has passed, I point out, that Groening can safely show his face in Australia. Which is exactly what he plans to do: the 62-year-old animator will present a talk, Secrets of The Simpsons, and with longtime friend Lynda Barry, Love, Hate and Comics: The Friendship That Would Not Die, at the Graphic festival.

"Australians are very forgiving," Groening says, smiling. "I was slightly appalled and embarrassed by our disrespect for the facts, but, what are you going to do? It's a cartoon."

The master's lair – he has another, more modern office, across town in Santa Monica – contains all manner of anachronistic jumble. A gleaming one-inch videotape player takes pride of place. And a VHS video-cassette recorder. Scattered around the room, on shelves, and in spare corners, are various items of bootleg Simpsons merchandise. Notable among them is a case of the unlicensed Duff beer pumped out by a South Australian brewery in 1996.

"It's folk art," Groening says of his obsession with bootleg merchandise, though he concedes he no longer collects aggressively for the most practical of reasons: he has nowhere to put it. "I used to try to collect it and then realised it's too much stuff," he says. "But there's a million things online and art shows of Simpsons-inspired art, which is pretty great."

Groening's talk at the Sydney Opera House will not be overly academic. "If anything, it's the opposite. I've been the victim of very dry stage presentations and it is my feeling as an audience member that I start paying attention whenever a panel discussion or a speech-giver gets off the subject.

"Then suddenly you go, oh, you feel like you're in the moment, and there's something unique and spontaneous," he says. "So, I will try to do that in Sydney."

The second element of Groening's appearance will be shared with his friend cartoonist Lynda Barry, whom he met at college. A brief history: Groening heard about a girl who had written a letter to Catch 22 author Joseph Heller, writing "Ingrid Bergman" on the back of the envelope hoping to bolster her chances of a reply.

"Inside she wrote, I'm not really Ingrid Bergman, I'm Lynda Barry and I'm a fan of yours, will you marry me?" Groening reveals, chuckling. "And Joseph Heller wrote back, saying, it's a very flattering offer but I don't think there's room enough for the both of us in your dorm room. It was really sweet."

Groening and Barry became immediate friends and lived large on the campus of Evergreen State College in Olympia, Washington. "No grades, no required courses," recalls Groening. "It was just fun to tweak the hippies. We were both hippies ourselves, but even back then people were easily offended."

After college, Groening moved to Los Angeles hoping to become a writer, taking a job on The Los Angeles Reader, which later published his comic strip Life in Hell. In 1985, he met producer Jim Brooks who, having seen Life in Hell, proposed Groening animate a series of shorts for The Tracey Ullman Show.

Inauspiciously perhaps, and with jagged lines and still uncertain voices, the Simpsons – Homer, wife Marge and kids Bart, Lisa and Maggie – were born. The names of Bart's parents and sisters were, like much of The Simpsons, borrowed from Groening's own life.

In 1989, they migrated from shorts into their own half-hour series and a bona fide cultural phenomenon was born.

"At first it was just refreshing because it took a very conventional format of low budget television cartoons and it was a little smarter and a little quicker than usual," Groening says. Later, he says, it was the collective effort of "great writers and great actors, great animators and great musicians" which elevated the show.

"We took the template of a family animated sitcom and we used it as a forum for all kinds of jokes, so there's parodies and slap stick and sophisticated literary references and musical numbers and homages to other forms of animation and politics and religion and everything."

Delving into the more complex aspects of the show's humour, or its social commentary, is a risky proposition. As with most expressions of art, the more you unpick the knots, the greater the chance it will unravel before your eyes.

"Comedy is very hard to analyse without killing it," Groening says. "That's a big fear of a lot of people who work with humour, [but] I feel though, if you can analyse humour and comedy and jokes, you may destroy some of your unconscious anxieties that drive you to do certain kinds of jokes."

For Groening, one of the most influential texts was Rationale of the Dirty Joke, written by Gershon Legman and published in 1968.

"Basically the author says all humour is based on hostility," Groening says. "It's very Freudian. And then [Legman] admits, given he has spent his entire life collecting dirty jokes and that humour is all based on hostility, that yes, he's a very angry guy. I thought that was great self-analysis."

For the record, Groening doesn't agree wholeheartedly. "I don't think I believe that all humour is based on hostility, [though] a lot of it is," he says.

In its infancy The Simpsons was seen as counter-cultural, even controversial. Here was this family whose father, Homer, was overweight and lazy, and whose son, Bart, was disrespectful, even uncouth, gasped the social commentariat. Never mind that the family solved problems co-operatively and that, without fail, they were in church together every Sunday.

In many respects the show's counter-cultural sensibilities came from Groening's childhood in the turbulent 1960s. "It was an exciting time to be in school because film, music, movies, there was just a revolution of styles and people were pushing stuff, pushing the extremes and reinventing themselves," he says.

Inspired by the "great experiment" of the 1960s, he found himself frustrated by the blandness of American television. "I thought, if I had a show, I would have a kid who is really bad on the show, instead of what passed for bad, which I thought was very namby-pamby," he says.

More than 25 years later – with almost 600 episodes, one motion picture, 31 Emmy Awards, one Peabody Award and the word "D'oh!" (Homer's "annoyed grunt") now officially in the dictionary – the series has not just shaken off its counter-cultural roots, but it has clawed its way to the very heart of the mainstream.

Groening declares he is baffled by both how constricted television used to be, and how '"absolutely free-form the wildest stuff is [now]. There's too much good stuff. When I was a kid there was hardly anything."

In comparison, he observes, The Simpsons "is relatively conventional these days, compared with the explosion in cable television cartoons."

Broadly, however, satire and parody are fighting a slow war of attrition with the increasing absurdity of the real world. Case in point: the US election, which has television satirists working overtime.

"The Simpsons is so much dealing with caricature and exaggeration; it is very hard to exaggerate the caricature that is reality," Groening says. "Specifically, this election. But we try."

He is a fan of HBO's John Oliver. "There are brilliant American social satires and political satires," he says. "My guess is, what little I know about Australian politics, it seems like it's just as crazy, it's just as much polarisation."

So, he has done some pre-departure research? Or at least updated the research he did for Bart vs. Australia?

"I decided I should become acquainted with some aspects of Australia that I don't know," he says, revealing an impressive shopping list of Australian literature: My Brilliant Career by Miles Franklin, The Fatal Shore by Robert Hughes and The Harp of the South by Ruth Park.

"Oh my gosh, it's fantastic," he says of the last of those, which he is presently part-way through. "I got the sequel [Poor Man's Orange] too. I got this beat up, used copy of both books with somebody else's name in them, but it's so good."

With no firm itinerary outside of his appearance at Graphic, Groening says he is simply looking forward to meeting the fans. The art of that interaction, he offers, lies in finding something unique to share with them.

And, he adds, never, ever correcting them on detail, even if they have spelled the name of a character incorrectly in a tattoo. We pause for a moment, and I ask him that ever happened?

"One of the very first fans I met, had my Life in Hell rabbit on his arm and it said, Blinky," Groening says. He pauses for effect. "His name is Binky. And I didn't say anything."

In fact, Groening reveals, his fans have historically displayed a disturbing tendency towards indelible ink. "I once ran into a fan in Baltimore, at a museum, and he said, can you sign my arm? And I did but I said, don't get this made into a tattoo," he recalls.

"And then he said he was going to do just that, so I said, you've been drinking, I want you to sleep on it, just don't do it tonight," Groening adds. "And an hour later he came back, his arm bloody, and declared, I did it."

Matt Groening's solo talk for the Graphic festival is at the Sydney Opera House on November for is sold out. Groening and Lynda Barry in Conversation is at the Sydney Opera House on November 5. See the Graphic web site for the full festival program.