What’s the most influential rock album of the 1990s? Easy: Nevermind by Nirvana. It kickstarted the grunge movement, obliterated the 1980s, and created an entire generation of grown-ups who still don’t know how to spell the phrase “never mind.”

But here’s a more challenging (and more interesting) question: What’s the second most influential rock album of the 1990s? Some might say Radiohead’s OK Computer. Others might nominate Beck’s Odelay. A few emo types might even mention Weezer’s Pinkerton.

They would all be incorrect.

That’s because the second most influential rock album of the 1990s is Dookie by Green Day. In honor of Dookie’s 20th birthday—believe or not, the LP was released on Feb. 1, 1994, a factoid that is guaranteed to make you feel old—I suppose I should explain why.

Before we proceed, a few caveats. Let the record show that I said “rock album”—not “album,” period. A lot of very influential rap albums (Dr. Dre’s The Chronic) and very influential R & B albums (The Miseducation of Lauryn Hill) came out in the 1990s, but that’s not the can of worms I’m opening here. I also said “influential,” not “best.” There’s a difference.

Even so, the first thing to note about Dookie is that it’s a remarkably good record. Go back and listen again. It’s undeniable. I remember hearing “Longview,” the LP’s lead single, for the first time—or rather, watching it. It was early 1994. I was 11 years old. I was checking out MTV after school, which is what I did back then, and MTV was playing music videos, which is what MTV did back then. Suddenly, the “Longview” clip came on: the scuzzy living room, the Newton’s cradle, the organ grinder’s monkey, Billie Joe Armstrong’s green forelock.

But it wasn’t the images that soldered themselves to my brain. It was the music. “Longview” is all hooks. The tom-tom shuffle that starts the song is a hook. Mike Dirnt’s circular bass line, which he apparently wrote while “frying on acid so hard,” is also a hook. (“It just came to me,” Dirnt told Rolling Stone in 1995. “I said, ‘Billie, check this out. Isn’t this the wackiest thing you’ve ever heard?’ Later, it took me a long time to be able to play it, but it made sense when I was on drugs.”) The smart, sinewy verse melody that sounds like what it’s describing—meandering and repeating while Armstrong sings about “sit[ting] around and watch[ing] the tube,” then impatiently resetting itself over and over when he arrives at the part about being “sick of all the same old shit”? That’s a hook, too. So is the nuclear chorus. Even Armstrong’s voice is a hook of sorts—the frustration and longing of adolescence distilled into an adenoidal half-English whine. Like it or not, it certainly gets stuck in your head.

I didn’t rush out and buy the album that afternoon or anything. But a little while later I heard some older kids talking about Green Day at my local CD shop. I saw the CD—with its anarchic, poop-dog-Where’s-Waldo cover—in the new-release rack. And that was pretty much it for me. I was in sixth grade at the time. I didn’t know that “Longview” was about masturbation and “smoking dope.” I’m not sure I even knew what those things were at that point. But over the next few years I learned, and Dookie was never far from my Discman. I can’t imagine an album better tailored to the pubescent experience, from the antisocial fantasies of “Having a Blast” to the fading friendship of “Emenius Sleepus” to the sexual confusion of “Coming Clean”—each of them crafted with the kind of Brill Building precision and performed with the kind of whiplash dynamics that can keep even the most ADD teenager from getting distracted. No wonder the album spawned three number-one Billboard Modern Rock singles—”Longview,” “Basket Case,” and “When I Come Around”—and sold more than 10 million copies in the United States alone.

So that’s why Dookie was great. But why was it influential?

Three reasons. The first was the debate it ignited—and ended. Dookie wasn’t just an LP. It was a something to take sides over. Punk rock was pretty popular when it first surfaced in the 1970s. Never Mind the Bollocks, Here’s the Sex Pistols topped the UK charts. The Clash hit number 12. The Ramones’ Rocket to Russia made the top 50 in the U.S. But after 1980 or so punk went underground. There, it developed the standard subcultural obsession with “cred,” and this is the scene—specifically the scene around Gilman, a legendary Berkeley, Calif. club—out of which Green Day emerged. Because Dookie was on a major label—and because its songs were so catchy and so unabashedly calibrated for maximum mainstream impact—punk kids took offense. Their earlier work on Lookout! Records is way better, they’d say. Now they’re sellouts.

People were really angry about this stuff; two months after Dookie debuted, half a dozen moshers attacked former Dead Kennedys singer Jello Biafra at Gilman and sent him to the hospital. (“Sellout rock star!” they shouted. “Kick him!”) But when Green Day blew up, the world didn’t end, and punk didn’t die, and partly because of this we no longer wage war over who’s a sellout and who isn’t. Nowadays, our attitude is healthier: it’s the quality of the music that matters, not the label it’s on or the ad it has or hasn’t appeared in. Popular music is at its best when it’s forced to respond to the marketplace and find artful, innovative ways of not only expressing its creator’s vision, but connecting with an actual audience. That’s why it’s popular music. Dookie is Exhibit A.

Which brings us to the second reason Dookie left such an indelible impression on the 1990s: it made the entire pop-punk movement possible. This was one of the defining genres of the decade, and in turn it shaped the way people looked, dressed, danced, and spent their summers. Odeley is fantastic. So is OK Computer. But neither record triggered the sort of commercial tsunami of compatriots and copycats that followed in Dookie’s wake. Blink 182’s first album materialized a year after Dookie; the group has sold 35 million records to date. The Offspring have sold more than 40 million. Rancid, New Found Glory, Sum 41, Fall Out Boy, Panic! At The Disco ... the list goes on. Sure, none of these bands ever released a record as thrilling as Dookie. But all of them tried—and because of Dookie, America paid attention.

Ultimately, however, I think that Dookie’s impact transcended pop punk. It actually shaped how the entire rest of the 1990s sounded. Before Dookie, guitar rock meant grunge: heavy, monotonic, humorless, and bleak. After Dookie, it meant something different—something brighter and sharper; something more melodic and even more romantic. Dookie bridged the gap between angsty Nirvana—Kurt Cobain died 10 weeks after the album arrived in stores—and the kind of tuneful six-string hits that came to dominate the charts as the decade wore on. “Good” by Better Than Ezra. “Buddy Holly” by Weezer. “Barely Breathing” by Duncan Sheik. “One Headlight” by the Wallflowers. Not that these bands sounded like Green Day. They didn’t—at all. But in some sense, Dookie was the pivot point. The world that preceded it was a little more rock. The world that followed it was a little more pop.

Of course, the world of music has changed many times over since 1994. Bands of three or four dudes with guitars and a drum kit have vanished from the singles charts; as far as I can tell, the last one to top the Billboard Hot 100 was Coldplay in 2008 (“Viva La Vida”). And Green Day is no longer a snotty little Berkeley punk trio: they’ve released rock operas and Broadway musicals and albums of Everly Brothers’ covers with Norah Jones. But if you need a quick reminder of what music was in the 1990s, crack open the Dookie jewel case and slip the CD into your car’s six-disc changer. As a wise man once said, “welcome to paradise.”