As with so many iconic TV characters, the first time viewers met Lisa Simpson was a pretty unforgettable moment.

In the very first episode of The Simpsons, Lisa makes a dramatic entrance during her elementary school’s festive pageant, which showcases how Christmas is celebrated in different countries around the world.

After her classmates are done with their own drab presentations about festive characters from Japan and Germany, Lisa enters the stage in a tribal mask and grass skirt as “Tawanga, the Santa Claus of the South Seas”.

The eight-year-old then proceeds to dance around the stage while juggling fire, oblivious to – or perhaps just unbothered by – the perplexed expression on the residents of Springfield’s faces in the audience.

The moment is quintessentially Lisa: it’s provocative, it’s intelligent and it shows the eight-year-old quite literally dancing to the beat of her own drum (it’s also probably more than a bit culturally appropriative, but it was 1989, and the chances that modern-day Lisa would deliver such a performance are pretty slim).

To a lot of Simpsons fans, the animated second-grader resonates in unlikely ways, as an outsider who doesn’t fit in with her surroundings. To many younger viewers, she was also a reminder that they weren’t the only ones who felt that way, and that’s why for so many, Lisa represents the emotional core of the show.

Even when the show is at its most madcap and zany, the chances are you can rely on her to bring some gravitas to a situation, and if not, then a lot of heart.

Although most TV critics agree The Simpsons didn’t enter its supposed “golden age” until the third or fourth series, one episode from its first run that’s consistently held up as a favourite also happens to be the first in which Lisa takes centre stage.

Moaning Lisa sees the character struggling with feelings of sadness for a number of reasons: her creativity is being stifled, she feels unappreciated and disliked by her peers and even her own family doesn’t seem to understand her. “How can we sleep at night when there’s so much suffering in the world?” she asks her father while sitting on his lap at the height of her angst.

Looking back at it almost 30 years on, Moaning Lisa would probably be the first time many viewers had seen a storyline which can be interpreted as a character’s mental health struggle – and in particular, a child’s.

Fortunately, Moaning Lisa ends on a high note, with the character working through her loneliness and making connections not only with her mother (whose tear-jerking speech to Lisa in the car is undoubtedly a high point in The Simpsons for both characters), but also with fellow saxophonist Bleeding Gums Murphy, who serves as a mentor to Lisa in later episodes.

Indeed, most of her most memorable and emotional scenes are when the usually isolated Lisa meets new characters who recognise traits in her that the rest of Springfield don’t usually have time for.

In the much-celebrated episode, Lisa’s Substitute, we see her becoming enamoured with Mr Bergstrom, a stand-in teacher who she feels truly seen by (again, who doesn’t well up thinking about his “you are Lisa Simpson” consolation in the train station).

Meanwhile, Lisa’s Date With Density sees her briefly dating school bully Nelson Muntz, after realising they have more in common than she’d originally thought. And even in Bart On The Road, her growing bond with Homer provides some surprisingly touching scenes, despite their obvious differences. 

Probably the most celebrated Lisa-centric episode is 1996’s Summer Of 4 ft. 2, which sees the character making new friends while her family are on holiday at Ned Flanders’ beach house.

Initially put out when Marge suggests to Lisa that she bring a friend along on their trip, she decides to completely reinvent herself, and falls in with a cool group who love Lisa, and completely see through her brother Bart, whose shadow she’s so often in back home.

At the end of it all, Bart exposes that Lisa has been downplaying her “nerdiness”, only for her new friends to accept her regardless, decorating The Simpsons’ car as a gesture to show they love her for who she is. It’s a touching moment, and one that serves as a reminder to those viewers who relate to Lisa in her lonely moments. And even if we don’t feel seen or valued by those around us, it’s just a matter of finding our tribe out in the world, and discovering the people who truly appreciate us.

Her emotional journey isn’t the only way that Lisa leads with her heart, though.

Compared to the rest of Springfield (including members of her own family), Lisa is an extremely principled character, determined to do the right thing, even if it puts her in trouble or makes her unpopular. And she is certainly unafraid to speak out against the patriarchy, whether that’s represented in Principal Skinner, Mayor Quimby or beyond.

A huge Malibu Stacey fan, Lisa is devastated when – in the episode Lisa vs. Malibu Stacey – a talking version of the doll puts out slogans that she sees as harmful to young girls, and devotes her time to creating a new doll with a more feminist message.

Meanwhile, after being crowned Little Miss Springfield in Lisa The Beauty Queen, the local government is perturbed when she speaks out about the corruption she sees in her city, to the point they strive to take her down and eventually dethrone her.

And in Lisa vs. The 8th Amendment, she’s even able to change her usually stubborn dad’s mind about his stolen cable with a silent protest, which he then insists the rest of the family take part in too.

But even when her opinions come from a place of love, Lisa also knows where to draw the line. In Lisa The Vegetarian, she apologises to her dad after a conversation with Apu (not to mention Paul and Linda McCartney) helps her realise that no one is perfect.

Similarly, in Lisa The Iconoclast, she learns the truth about the town’s founder Jebediah Springfield’s secret past as a villainous pirate, but after being given the opportunity to tell the world, she holds her tongue, ultimately deciding: “The myth of Jebediah has value too, and it’s brought out the best of everyone in this town.”

And in the cases where she’s done wrong, Lisa is unafraid to own up to her mistakes and try and make things right. At the end of Lisa’s Rival, she saves a fellow student after trying to sabotage her efforts in a school project, and when she inadvertently humiliates Ralph Wiggum in I Love Lisa, she’s determined to make things right between them.

Much has been made of the various “predictions” that The Simpsons have made, the most famous of which was the fact that Donald Trump would one day be president, more than 15 years before he’d enter the political race.

If there’s any comfort to be taken from this, it’s the fact that Lisa Simpson went on to be his successor in the same episode, and even though she’s eight years old and spends much of her time playing with Malibu Stacey and racking up her family’s phone bill with the Corey hotline, she’s a candidate we’d be happy to endorse.

Principled and intelligent, but also keen to share her knowledge and ideas with others, Lisa also counteracts the majority of the characters in The Simpsons with her sensitivity and compassion, and for that reason, she’s undeniably the heart of the show.