When I stepped off a ship last October after a month at sea and saw the Golden Gate Bridge in the distance, gleaming in the morning light, my heart fluttered. It was the same giddy feeling I’d had the first time I saw the bridge, 25 years ago, when I drove someone else’s Buick Riviera all the way from Denver to California and finally through the tunnel that frames the bridge’s magnificent towers, the bay and the city beyond: I’m home.

But as I disembarked, I had to rub my eyes as it slowly dawned on me that the Golden Gate Bridge was not where it was supposed to be. It was in Lisbon, of all places, and I wasn’t yet home. I was staring at the 25 de Abril Bridge—built by the same company that constructed the Bay Bridge and painted international orange; a San Francisco mutt of a bridge—and I yearned for the real thing.

That Portuguese bridge, built with 2.2 billion escudos and as many good intentions, sort of spoiled my trip to Lisbon. Not that Lisbon isn’t a fine place to visit: It’s full of cheerful tile-faced houses, nice statues of Vasco da Gama, excellent grilled anchovies and boutiques where French clothes cost a lot less than they do in France. But even though Lisbon is an old town—settled 3,000 years ago and founded, legend has it, by Ulysses himself—the capital was destroyed by an earthquake and rebuilt 20 years before the Spanish ever laid eyes on Mission Dolores, and that faux bridge kept making me feel like the city was a second-rate San Francisco. Hills? We’ve got hills. Hippies with tattoos? We invented them. Ocean, wine bars, restaurants? Check. And you call this an arboretum?

Perhaps because I’d traveling for more than two months, I felt homesick. But San Francisco always tags along when I travel, eventually making me feel jaded about even the most exciting places. Paris seems so gray and serious next to San Francisco’s coastal light and whimsical dollhouses. Helsinki is matter-of-fact and boring compared to our free-spirited city. In Manhattan, 200 people snake in a line through Trader Joe’s just to buy dinner, the storied Greenmarket has paltry pickings compared with the Ferry Building, and the sidewalks are slush pools in winter (or it’s beastly hot and muggy in the summer). Don’t get me started on Los Angeles.

That sense of comparing everything to home doesn’t just happen in the cities. I can be standing on the cliffs of a pristine Sardinian coast, awestruck, and the thought will occur to me: “This is almost as pretty as Point Reyes.” When I rent a bicycle in Stockholm and pedal through its lovely parks, I can’t help thinking that from my house in the Haight, I can bicycle across the bridge into Rodeo Valley and see a bobcat in the wild.

So why travel? For one reason, I can’t help it; as Vita Sackville-West wrote, “I have got the Wanderlust, and got it badly.” San Francisco attracts free spirits (it has the highest population of Aquarians and Leos per capita of any major city, and if I need to explain that to you, you haven’t been here long enough), so I’m at home where I’m restless. For another reason, my neighborhood is foggy and depressing as hell in the summer. Some days I feel as if I’ll scream if I see another grimy suburban kid eating old pizza crusts in front of one of Haight Street’s 18 head shops, trying to sell the contents of a free box for buds. Other times, San Francisco seems too precious and pretty: When I watch people in Hayes Valley waiting 45 minutes for a fetishistic cup of coffee, I want to flee to a country where they draw you a quick, perfect espresso, as they’ve been doing for centuries, and you can bolt it down at the bar and get on with your life.

And so I travel. Sometimes I’m so infatuated with a place I forget about San Francisco for a while. Southern Italy silenced the craving I always have at home to be perched on a stool at A16 watching baby fava beans drizzled with olive oil come out of the oven, or sitting at a table at La Ciccia eating pasta fregola or grilled fish. In Tallinn, Estonia, I was too enchanted with the winding medieval alleys and blossoming trees to consider how much I love walking the quaint and curvy streets above my neighborhood, and how lovely the pastel Victorians on my street look when the periwinkle-blue ceanothus trees are in bloom.

After a week or two of traveling, SF starts cropping up in my consciousness, often as a negative comparison, the way a new crush sitting in a cafe always seems more handsome and exciting than the guy watching DVDs on the couch back home. In Copenhagen, I cursed San Francisco’s bike lanes, which you have to share with Muni buses, while northern European cyclists have concrete barriers between themselves and 10-ton vehicles. St. Petersburg made me realize how puny our museums are compared with the collections of Catherine the Great and subsequent Soviet plunderers.

But that initial phase doesn’t last. After a month on the road, San Francisco beckons irresistibly, no matter where I am. Two years ago, I was so tired of the fog in this town that I bought a little house in San Miguel de Allende, Mexico (where real estate is considerably less dear than in SF), thinking I’d live there half the year. I thought I could be happy in that artsy colonial community, eating tacos, listening to live music, and basking in the brilliant sun. But little by little, SF snuck up on me. The vegetables in San Miguel were shabby and tasteless compared to the ones at home, and there was nowhere to buy Greek yogurt, not to mention bottarga. The burritos in the Mission were better. Mexico’s yoga teachers weren’t as good as mine. I missed the community of writers I work with, South Park on a sunny day, skimming through the shelves in the Booksmith, the shopkeepers on Haight who know me by name, running into random friends I’ve made over 25 years and bicycling across the real Golden Gate Bridge.

Little by little, I’ve found myself spending less time in my second home than I’d imagined, and more time in my first. That’s the best thing about being a San Franciscan: My wanderlust gets to thrive in both directions.

Laura Fraser’s first memoir, An Italian Affair (Pantheon), spent 22 weeks on The New York Times best-seller list; the sequel, All Over the Map (Harmony), hits bookshelves June 1.