After about my first week in Spain last quarter, I’d learned a couple valuable lessons: If you ever have to tell someone you’re American, say you’re from California. And if you have to tell people you’re from California, it had better be San Francisco.

So, accordingly, that’s how the story went: A native of the city (never “San Fran” or “SF” — always “the city”), I’d come to Barcelona to improve in Spanish, bask in the Mediterranean sun, blah blah blah. Where appropriate, I’d maybe mention my school in a forgettable little town of flip flops and ceaseless sunshine called San Diego, but mostly I projected the fantasy of a life spent traversing urban hills — a constant, treacherous undertaking to be paused only for the sake of talking about progressive ideas with other progressive people or hitting up the nearest gay bookstore. Such was the life of a San Franciscan.

Seldom would I mention the reality of my roots: suburban flatlands half an hour south of the city; Barnes & Nobles with “Out” and “The Advocate” and occasionally something in parental-advisory plastic wrap at the top of the magazine rack. Never would I have anything positive to say about the sprawling, cultureless vacuum 300 miles down the coast that is Los Angeles.

The NorCal/SoCal debate isn’t a new one at UCSD, and inevitably devolves to a back-and-forth on about three points: burrito quality, year-round climate and the superfluous use of the word “hella.” In Spain, it was nice, for a change, to spread the gospel of the Bay Area rather than argue the usual pros and cons.

But despite any deeply ingrained, groundless prejudices against the City of Angels, after a month back at school, I needed at least a couple days away. When a friend offered up a mattress at UCLA last weekend in exchange for a ride, I suspended my judgment and packed the car.

While I’m not quite ignorant enough to believe my 36 hours there summed up everything L.A. has to offer — I didn’t, for starters, get to watch Lindsay Lohan being dragged in handcuffs from Forever 21 — I think I covered most L.A. college-student bases.

I window-shopped at recession-unfriendly retailers; I watched the sunset from the Santa Monica pier (O.K., definitely not the stuff of true Angelenos); at night’s end, I gazed, awe-struck, at the six-foot-long letters gracing the bottom of a frat-house swimming pool. Because real fraternities own 6,000 square-foot houses with custom swimming pools, apparently. There’s one lesson my UCSD education failed to impart.

My friends from L.A. insist that the city changes you. No matter your place in society, I’m told, you can’t leave without a haircut, multiple shopping bags and a renewed sense of self-loathing. I’ve always been a little skeptical: Sure, L.A. may be a miserable enclave of the self-absorbed, but it couldn’t be that powerful. No way. It’s not like there’s anything but fluoride and chromium in the water.

Oh, how wrong I was. Eighteen hours in, I’d found myself in Santa Monica, Coffee Bean cup (a la Mary-Kate Olson) in one hand, Fred Segal shopping bag in the other. I’d long since realized the urgent need for a new hairstyle when someone asked me what brand my shoes were. I told him, none too bashfully, that people don’t just ask questions like that at UCSD, that that kind of thing was stupid and shallow and didn’t matter. (Then: “Ted Baker.”)

You might not expect the grass to be greener with all that pollution and insecurity in the air, but driving down Sunset Boulevard on the morning of our departure, pulled up at a stoplight next to a commercial filming in progress, it was impossible for my friend in the passenger seat — an actual San Franciscan — to contain her wonder: Was that the Chateau Marmont? Were we really about to turn onto the Hollywood Walk of Fame?

“You know,” she said, head turned toward the passing monuments to Barbra Streisand and Destiny’s Child, “I can almost see why people might like living here.”

Eyes focused on the road ahead, squinting to make out another camera crew or the sign for Interstate 101-S, I vocalized my assent (“um, yeah”) and continued out into the smoggy unknown. If we’d stayed too much longer, I’m afraid, I might have forgotten all about the gospel of the Bay.