If you ask the thermometer on my car dashboard, summer is in full swing. But Sophie goes back to school next week so we’ve been washing backpacks, shopping for highlighters and generally returning to reality after several weeks of travel.

Last week the girls and I dragged ourselves away from the beach, moving slowly to the already-packed car.

“One sec!” Sophie called, stopping in front of the hotel gift shop. “I have to say good bye.”

I was confused — I hadn’t bought her anything all week, we hadn’t even browsed together in the shop. But sure enough, the young woman behind the counter greeted Sophie by name, offering a hug and wishes for a safe trip home.

Annabelle and I smiled. Of course Sophie knew the clerk at the gift shop. She must have been stopping in on her way to the pool.

It’s true that Sophie loves to shop. She gets it from me. I like to say that it’s not hoarding if you stick what you buy in cute bins with labels, but the truth is that I hunt and gather like my life depends on it — and my younger daughter has inherited the gene. She knows what she wants: leggings from Target, foundation from Walgreens, goldfish AND cheddar bunnies at Safeway. A new pop socket, a particular brand of sticky rice, crop tops, Vans.

But mostly, I realized this summer, Sophie is shopping for friends.

She’s got her sister, her nannies, her cousins, her father and me. But the truth is that Sophie spends a lot of time alone. There are no play dates (or whatever you call them when you’re 16), no sleepover invitations.

On one level, I would like to torch the entire world on my daughter’s behalf. Sophie is the best friend that anyone could ask for: loyal, kind, interested, loving, fun.

On another, I get it. Sophie is intense. Her love is fierce and she demands a lot more attention than her peers have got to give — or should be expected to offer. If she’s playing a video game with a friend online, she might not understand when that friend needs to take a break. She texts constantly and calls even more often. (My phone rang twice while I wrote this paragraph.) She has trouble with boundaries.

And yet she craves interaction. So who better to befriend than a store clerk — a captive audience with one job: to engage with the shopper.

Funny, it’s been going on for years. But I didn’t realize it till I had a chance to observe each member of my family in action at a store.

At the end of June we drove up and down the California coast and saw so much — beaches, boardwalks, Andy Warhol’s drawings, Katy Perry’s favorite taco shack, the flower mart in Los Angeles, breathtaking views of Big Sur. We glamped in Santa Cruz and survived a night at the Madonna Inn, an acid trip of a hotel in San Luis Obispo that I thoroughly recommend.

But one of my best memories of the trip is the smallest — from a morning in San Francisco’s Japantown, most of which was spent in a tiny stationery store in an indoor mall filled with teriyaki restaurants and boba stands.

I can count on one hand the things each member of my little family of four loves equally and with abandon — standard poodles, Paul McCartney, Irish soda bread on Christmas morning.

And writing materials.

Ray made a beeline for the journals. He examined them thoroughly till he found just the right one, showed it to me, announced it was overpriced, put it back — and parked himself on a bench outside the store to wait for the rest of us.

I scooped up the journal (his birthday was the following week) and snuck it in with the pile of greeting cards, pens, folders and washi tape I had no business buying.

Annabelle stood in one spot for 45 minutes, trying every single shade of her favorite brand of pen, finally choosing three.

And then there’s Sophie.

Before the rest of us were over the threshold she was standing in the middle of the crowded store, demanding the attention of a young woman who worked there.

“Do you have pens?” I heard her ask, even though she was facing an aisle that held thousands. “Mechanical pencils? Can you show me?”

As they walked away I heard her favorite opening line. “I like your sweater. Where’d you get it?”

American Eagle. It seems like they are always wearing sweaters from American Eagle. This young woman had dark blue lipstick and cranberry red streaks in her long, dark hair. She smiled and spent what seemed like forever patiently showing Sophie each brand of mechanical pencil the shop carries.

The clerk tried to offer Sophie a selection of lower priced items, but still my kid presented me with a $25 journal and a $15 pen. She knew better than to ask for the $29.95 paintbrush.

I waited her out and Sophie chose a handful of cheap pencils and a small journal. But she walked away with so much more. I’ll think twice before I say no to the next shopping request.