My husband, like me, is a painter. He’s also an art critic, and in this capacity gets invited to a lot of interesting art events that we go to together. Last Thursday evening, we attended a small (40 or so people) dinner party at the Metropolitan Museum of Art, hosted by its president, Emily Rafferty. As an artist, I always look kindly on happenings like these. They combine free food with the never-dying artist’s fantasy that a career can be skyrocketed into orbit on the basis of one fateful meeting. Plus, fancy events offer me the opportunity to wear one of my two fancy outfits — a thrill, since I never got over the dress-up corner in kindergarten.

The Met was closed when we arrived, and no one but security and party people were present. We went first to the roof, for cocktails and hors d’oeuvres. Even Jeff Koons’ shiny metal, big-and-blank balloon-dog sculpture (“Koons on the Roof” is one of the Met’s current shows, running through October 28th) couldn’t ruin the view of Central Park—that glorious, 150-year-old rectangle of artificial nature designed by Frederick Law Olmsted and Calvert Vaux.

At the end of the dinner in a terrace dining room, Ms. Rafferty announced she had a surprise for the guests: We were free to go anywhere in the Met and stay for as long as we wanted. Manna from heaven! To be alone in front of great paintings is for painters about as close to heaven on earth as we can ever get. And if you’re not a painter, but a parent, and your child has read E. L. Konigsburg’s From the Mixed-Up Files of Mrs. Basil E. Frankweiler (the story of a sister and brother who run away from home and hide out in the Met, first published in 1967), you, too, will understand how thrilling being alone in the Met is. (We weren’t absolutely alone, of course; a guard trailed along at a discreet distance.)

First stop: the early Flems. We stared, practically nose-to-canvas, at madonnas with poignantly ordinary Belgian faces, tenderly, exquisitely painted, filled with delicate details. Next stop: the Rembrandt room, which also contains a few other Dutchmen of note, namely Frans Hals, the fastest brush in the West. To paraphrase the famous comment about Monet’s eye: maybe only a wrist, but what a wrist!

We finished up with the 19th-century rooms. There the paintings have been recently re-installed with the inclusion of a lot of previously sequestered, but really good conservative pictures. The result is that the Met’s 19th-century collection is about the best education you could get in how what most people think of as “Art” (French academic painting and similar) morphed into modernism. On the muted hues of the redone walls, the breakaway colors of Impressionism and Postimpressionism glowed as if lighted from behind.

I stood in front of Cézanne’s struggling veridian green and ochre landscapes, watching the way his brush strokes build, one at a time, into a tentative and anxious summation of his perceptions. If you’re a painter—and maybe even if you’re not—you’re close enough to the canvas to feel as if your own “phantom limb” is putting on the paint. (The feeling is especially delicious if there’s no one else around; it’s almost like you’re standing in Cézanne’s place.)

We were standing in front of a dynamite wall of five van Goghs, when our guard came over to say, “Can you stay here a minute? I need to escort another couple to the exit.” Certainly, we said, somewhat in disbelief. Alone in the room, we said very little to each other and merely stared at the Cézannes, Gauguins, and van Goghs. After a few minutes, my husband said, “You know, there might be something to this business of being a billionaire — getting up in the middle of the night, putting on a silk robe, pouring yourself a single-malt, and wandering through your art collection.”

When our guard returned, we chatted with him. He said that he frequently walks the entire length of the Met three or four times in a given day. I asked him if he was an artist (museum guard is a day job sought after by many artists). He said no, that he was “just a guard.” But he added that he, too, loved being alone with the paintings, which he got to do at the end of each working day. He then said he’d taken his young son to the Frick Gallery, the smallish Old Master museum half a mile down Fifth Avenue, and owing to his on-the-job experience, he’d been able to identify almost every last painting.

Eventually, it occurred to us that it was only fair that we finally go home. “Fair,” plus the fact that pulling an all-nighter was impossible: We were the last dinner guests to leave, and as we made our way out of the museum, we looked over our shoulders to find a veritable army of guards following us to the exit.

Possible sore feet and obstreperous visitors notwithstanding, we envied those guards somewhat for being able to be alone in the Met, even for a little bit, every single working day.