Hey, what’s that sound?

Amy Winehouse in 2007, the year "Rehab" became her signature song.Matt Dunham/Associated Press

The thing about being a music lover is, you simply never know when it will hit you.

It doesn’t matter if you’re a critic sifting through dozens of promos provided by publicists or a civilian within earshot of a radio station or streaming service; one minute you can be listening to music and the next it can feel like your nervous system has just become a live wire. To be a music fan is to chase that sensation.

Of course, not every song we love hits as immediately as, for instance, the 3½ minutes in 2007 when I was flattened the first time I heard Amy Winehouse’s “Rehab” and became convinced for months afterward that it was the single greatest thing that existed anywhere in the universe. (That’s silly, of course; it’s only in the top 20.) And not everything that hits immediately lasts beyond the moment of discovery.

But that wonderstruck sensation is one of the great delirious joys of being a music lover. There’s something elemental to the very act of being a music fan about falling so deeply in love with a song or artist that you trip over yourself investigating what comes next. Sometimes you end up someplace you couldn’t have imagined, as when the Beatles’ happy “Let It Be” trifle “For You Blue” so captivated me as a teen that before I came back up for air I had taught myself to play guitar, leading to a better understanding of how music is put together. (I still can’t play “For You Blue” and in fact refuse to try.)

The Beatles in a recording session for their "Let It Be" album, as shown in the docuseries "The Beatles: Get Back."Disney+

Time was, falling down rabbit holes like that was mostly the province of the invested; you had to work and wait and dig and pay to acquire an encyclopedic knowledge on the musical object of your infatuation. In our current binge-happy era, with streaming services, instant digital library lending, and an Internet full of unimpeachably accurate information available at our greedy fingertips at the speed of thought, it’s possible to hear a song that buzzes your pleasure buttons over lunch and have albums’ worth of material and magazines’ worth of background under your belt by dinnertime.

And it all stems from that initial thrill of discovery. I’ve had two big ones in 2021, one that exists almost purely as itself and another that shows how far afield these things can lead. Sometimes, a thunderbolt is just a thunderbolt, which brings me to Wet Leg. The Isle of Wight band’s “Chaise Longue” is an artsy post-punk thing with deadpan female vocals, a prominent high bass, a propulsive motorik beat and a dryer-than-toast sense of humor. They would be the perfect act for me to get lost in for hours, if only they had more than four songs to their name. No matter; my brain keeps buzzing while I wait.

My other musical deep dive of 2021, meanwhile, boils down to simply a bunch of strangers talking about music and offers countless paths to follow. With his “The Number Ones” column, very tall Stereogum critic Tom Breihan has taken on the insanely simple, insanely ambitious task of reviewing every single song to hit No. 1 on Billboard’s Hot 100 chart since its inception in 1958. After stumbling across it two or three times, I felt a shiver that compelled me this past summer to zoom straight to the beginning (first entry: Ricky Nelson’s “Poor Little Fool,” rated 3 out of 10) so that I could devour every entry in sequence; Breihan has reached 1991, I’m currently in 1983.

As a music critic, I’m in awe and furious with jealousy. It’s been a revelation watching pop music evolve, sometimes in leaps and bounds and sometimes seemingly not at all. Breihan provides thorough research and context to his analysis, so that when he defies conventional wisdom — see his controversial ratings of “Penny Lane” and Freddy Fender’s “Before The Next Teardrop Falls” — it comes across as honest rather than smugly contrarian.

But it’s also been a marvel watching the column itself evolve in real time, with recurring features adding a satisfying continuity from column to column and the comment section flourishing into a smorgasbord of its own addictive subfeatures, from side trips into what was happening elsewhere in music at the time being discussed to one commenter’s entry-by-entry recounting of growing up as a pop-attuned Catholic schoolgirl that plays as a breathtaking adolescent soap opera. There are running jokes and a healthy respect for disagreement.

In essence, it’s a communal chronicle of all the ways that a single song can set you on fire. For a pop music fan, it’s catnip. For a rabbit hole enthusiast, it’s gold, providing not just an ongoing treasure trove of music criticism and journalism but also a rabbit hole of music itself, courtesy of both the column and its commenters filling in the wider picture of the artist’s work and contemporary music on and off the charts. It’s rabbits chasing rabbits. And while the path of the column is set firmly in the historical record, the nature of it means I have no idea where it will lead. Just like a great new song that’s suddenly your favorite thing in the universe.

Marc Hirsh can be reached at [e-mail] or on Twitter @spacecitymarc.