If I had to point to one album that completely changed the way that I think about music, it would be The Con. It was my gateway to really giving a shit about music — how it’s written, the way it’s made, the personalities behind it. Before, songs were just songs and albums were just albums, but The Con started me down the path of actually wanting to write about and be involved with music — interrogate what makes it work and figure out why it doesn’t when it doesn’t. I’m not the only one that feels this way, which I’ve only realized over the last couple years when talking to people who were impacted by Tegan And Sara in the same way. The duo just announced a covers album featuring 14 different artists covering each of the album’s songs, and last week NPR published a great feature with recollections from some of the contemporary musicians that were inspired by the Canadian twins, and most of them had discovery stories similar to mine. Tegan And Sara acted as a gateway for a lot of people, and The Con — which turns 10 today — is perhaps their most enduring legacy. It served as not only a catalyst for my own personal transformation, but marked a turning point for the duo, who a few years after this would make the transition from indie stalwarts to fresh voices in the pop world.

Tegan And Sara’s ascent was gradual and not at all easy, but part of their rise can be attributed to how accessible Tegan And Sara felt, especially to an awkward 15-year-old queer kid growing up in the suburbs. Starting with So Jealous, the Quin twins documented practically everything they did while creating an album, letting their fans see inside their process in what felt like real-time. The full-length The Con documentary that accompanied every CD felt almost as vital and important as the album itself. Watching that was the first time I ever saw what the inside of a studio looked like and got a sense of how it worked. Music can often feel like such a nebulous thing, but Tegan And Sara were eager to show how it lived and breathed, to display the hard work and labor that goes into the creative process. In an early social media age, Tegan And Sara leveled the playing field between listener and artist, feeling more like friends than some unattainable other. Through YouTube videos and personal blog posts and the songs themselves, they created an intimacy among fans that would in turn make those fans more comfortable and willing to create themselves.

A decade on, Tegan And Sara have become a respectable institution, but for the first half of their career they were plagued by the sort of sexism and homophobia that, unfortunately, is exactly what you’d expect from an industry dominated by straight dudes. Since the start, the sisters were unwilling to shy away from or feel ashamed by their sexuality, and they also refused to become defined by it, no matter how much outside forces attempted to make that the only part of the conversation. When The Con was released in 2007, Pitchfork characterized them as “tampon rock”; Rolling Stone prefaced their review by saying that they were “lesbians who never reference their oppression or sexuality.” Those crass dismissals stung — the duo recently posted a note reflecting on how harshly the press treated them early on — and they also made those that loved them fiercely loyal to and defensive of them. As Tegan And Sara’s legacy has solidified over the years, the young and queer people that they inspired would help to reposition their place in the canon. And, in retrospect, all that side talk is infuriating because The Con is so obviously a top-notch album — one of the best of the decade it came out in — and still stands as Tegan And Sara’s high water mark.

The Con represents a potent distillation of the sounds that the duo had been working with throughout their first four albums: So Jealous’ scratchy acoustics, If It Was You’s folksy punk, This Business Of Art and Under Feet Like Ours’ willingness to take risks and, at least on those early albums, occasionally fall flat on their faces. With The Con, they significantly expanded their sonic palette — no two songs on the album are the same — but they still sounded like nobody but themselves. It’s a rare artist that can take songs that are as different as “Hop A Plane” (a pepped-up scorcher) and “Soil, Soil” (a lovely, lonely ballad in miniature), put them side-by-side on a tracklist, and get away with it. But The Con is as varied as it is cohesive, and these songs play off each other like firecrackers while still feeling like one consistent slow-burn.

The songs that Tegan And Sara came up with for The Con were weird on the surface, something that’s especially apparent when trying to listen to them with fresh ears 10 years down the line. At this stage in their songwriting development, the twins were interested in finding hooks in unconventional places, preferring to relegate the catchy parts of their songs to the instrumentation. Take The Con’s two singles, “Back In Your Head” and the title track — their immediate draw isn’t in the words but in the intense shuffling keyboard on the former and the chunky guitar riff on the latter. And even in places where their lyrics serve as the primary pull, like on “Relief Next To Me,” it’s in the way that Sara emphasizes each line’s monosyllabic breakdown, how her words bleed from one phrase into the next: “Like curtains waving in and out of wind/ In and out of windows.” It’s the delivery of these songs that make them so memorable and endlessly repeatable. The smooth hooks that would come to dominate their more recent albums started to take shape here, but they kept their irregular edges.

The offbeat stylistic choices that Tegan And Sara made on The Con are indicative of how confident they were becoming as musicians. Part of that had to do with how their creative process was opening up with this album. Previously, they had largely worked apart before coming together in the studio, but for The Con, while they still wrote their songs separately, they gave each other more input during the writing process than ever before. They were in constant contact, bouncing ideas off of each other and slowly building up the tracks themselves. The duo made their demos available alongside the release of the album — another way they were transparent about their process with the listeners — and it’s clear from listening to them how much their collaborative efforts helped pull the disparate pieces of the album together. The sisters are in sync on The Con, and that spirit of intermingling would grow even stronger with time.

Based on the demos alone, The Con would have been special, but the cast of collaborators they brought together in the studio also helped to open up new possibilities for the duo. They recruited Death Cab For Cutie’s Chris Walla to produce the album. He saw the potential in those demos and used them as the baseline, trying to recreate their spontaneity as closely as possible. The takes that made the final version of The Con don’t sound like they’ve been practiced over and over; instead, they relish in imperfections and odd quirks. In the studio, they used household items like staplers and sunflower seeds to create sound effects. Elements of the demos show up in almost every song — the crackles and pops in the vocals on “I Was Married” were carried over directly from the demo, which Sara recorded with a cheap microphone in her bedroom closet. For closing track “Call It Off,” Walla used a recording of drummer (and then-DCFC bandmate) Jason McGerr breaking down his kit; if you listen closely enough, you can hear the unstructured percussion clacking away in the background.

Tegan And Sara utilized different bassists for their own songs on The Con: Tegan used AFI’s Hunter Burgan, who she was working with at the time on a side project that never came to fruition, and Sara chose Matt Sharp of Weezer and the Rentals, who played keyboards and synths on So Jealous. Guitar wiz Kaki King also contributed to the album, lending her pluckily-layered sound to “Knife Going In” and “Floorplan.” The different playing styles on display throughout the album help add to the variation in between songs but, in the end, Tegan And Sara’s strong creative voices are what tie everything together. The Con arrived in the studio pretty much fully-formed — they went in with a tracklist already laid out — and, while it morphed and grew from there, the essence of the album remains with the twins.

In addition to being in sync musically for the album, their personal lives also happened to be lining up thematically. When The Con was written, Tegan had just ended a five-year relationship and Sara was in the last throes of her own. Since the beginning, the duo has written songs about love and its many complications, but The Con is their bleakest and most pessimistic work in that regard. The songs on it deal with the value judgements that come with commitment, knowing that it could and probably will end in disappointment. The Con is about the lies we tell ourselves and others in order to maintain a facade of happiness. “The act of conning somebody, or conning yourself, that whole thing was a catchphrase I was using,” Tegan explained. “I think these songs on the record are under the umbrella of what a con represents.”

And all of the songs play on some variation of that theme. There’s “Nineteen,” which looks back at a failed adolescent love that makes you wonder why we bother trying again: “I feel you in my heart and I don’t even know you/ And now we’re saying bye, bye, bye.” “I’ll hold this loss in my heart forever,” Sara sings on “Floorplan.” The pair of songs that end the album, “Dark Come Soon” and “Call It Off,” play off like they’re having a conversation with each other: “Maybe I would’ve been something you’d be good at/ Maybe you would’ve been something I would be good at,” Tegan sings on the latter. “Everything I love, get back from me now/ Everyone I love, I need you now,” she sings, conflicted, on the former. The Con explores the ephemerality of the connection between two people and the self-deceptions we’ll believe in order to maintain some level of normalcy. But it doesn’t feel embarrassed by the confusion and frustration that love can offer; it’s as “heart-on-sleeve” as music can be, recognizing the warmth and comfort in finding someone else to share the world with while still questioning whether we can find that same strength within ourselves. The Con asks hard questions and doesn’t provide easy answers.

It’s that lack of clarity and intense vulnerability that makes The Con such an enduring listen. As transparent as Tegan And Sara were about their creative process, they were even more open and honest in the songs that they wrote. The Con serves as a testament to their abilities, which would only grow more ambitious and focused over the rest of their career. What I’ve come to value most in music — powerful narratives, complex feelings, emphatic outsider voices — can all be traced back to The Con. Tegan And Sara acted as the jumping-off point for those who echoed their alienation and desired their bold accessibility. They inspired a generation of listeners to take solace and find power in their emotions. That’s a legacy to be proud of.