Flash mobs have given Center City an unfair dose of bad publicity - "totally unwarranted," I assure out-of-town friends who write with great concern about our safety.

It's the white-collar rabble from Rittenhouse Square you need to watch out for if a recent meal at Serafina is any measure. Yes, this jam-packed new Italian at the corner of 18th and Sansom has more high-society "mob scene" about it than urban flash, the clientele so swank, Shore-tanned and crisply pressed they could be extras for the latest Bravo reality show. But one wrong bump of a chair beside the sardine-squished bar, and we were suddenly looking down the threatening outstretched finger of a silver-haired grump in tortoise-shell glasses and pinstripes. He'd risen from his plate of filet mignon carpaccio to snarl that we had callously disturbed his wife.

"I'll knock you out," he wheezed to one of my guests, whose apology, apparently, was not accepted.

Manager Rose Parotta, the supreme soother of Market Street egos since her days at the Happy Rooster, ably placated Mr. Snarl with a pour of limoncello. But the tantrum did lift all in his orbit on edge - at least those few who could hear through Serafina's wall of sound, like a server who rolled his sympathetic eyes while passing our table: "This is not the place to be if you don't want to be touched."

Serafina, with its stupidly oversized bar crushing food-runners, guests, and packed tables into a noisy lasagna of a space, seems almost designed for full-contact dining. And while the room is done up with colorfully striped banquettes and whimsical frescoes of flying eggplants and floating ziti, the karma here is steeped in indigestion.

The kitchen doesn't help, turning out a vast but prosaic Italian menu that, by Philly standards, is dull, relatively expensive, and soullessly mass-produced. Who could try to digest a plate of these over-fried calamari, seemingly spring-loaded for maximum chew; a pile of paglia e fieno fettuccine tossed in overthickened blush sauce; or a minuscule fillet of bass cooked to mush inside a shaved potato wrapper for $26, and still want to return?

Apparently, there are 300-plus diners a night who have been flocking to this corner with the same name-brand determination that drives the style-conscious to want anything with a New York pedigree.

But I can see why co-owner Vittorio Assaf has recently, after two months of shaky rowing by the crew here, brought in a ringer chef, Fernando Pilego, from his 61st Street branch in Manhattan (Derek Jeter's favorite), to right the Rittenhouse ship. While he's at it, he might also consider finally removing the "opening spring 2011" yellow construction decals that still wrap the upper windows.

Serafina has certainly cultivated a luxe cachet in metro New York with a dozen or so locations (plus forthcoming outlets in Brazil, Moscow, and Istanbul), presumably not with such a weak performance.

This isn't meant to be elaborate or creative cooking. It's meant to showcase familiar flavors with a light, natural touch on pastas, pizzas, and carpaccios - with plenty of mix-and-match options - highlighting good ingredients: "Almost Venetian," a manager told me.

But at my meals prior to the arrival of the N.Y. chef (supposedly just last week), this kitchen struggled with the finesse required to give such subtle dishes taste. The minestrone was pale and bland with mushy veggies. A plate of prosciutto and mozzarella (how simple is that?) was dimmed by ham sliced too thick, and mozzarella that was dry and bouncy. A veal carpaccio streaked with truffle sauce was oddly icy (a symptom, perhaps, of too deep a freeze before being sliced). The tuna carpaccio had the amber translucence of something that had sat out too long, and a fishy aroma you don't want from your sashimi.

The undressed greens on many cold starters had the half-wilted look of a work-ahead prep kitchen. Big chopped salads, like the Porto Cervo with hearts of palm, avocado and corn had the personality of something from Saladworks. The San Pietro plate of baby shrimp, white beans, avocado, and mustard sauce was a far better place to start.

Brick-oven pizza is one of Serafina's calling cards, but in the context of our current pizza revolution, these were fairly middle-of-the-road. The crusts are ultrathin, with little to no puff on the edges, and the tomato sauce was extremely salty on our Margherita, though contrasting to the sweetness of the buffalo mozzarella. The Bianca white pie with arugula, Fontina and Parmesan was a better bet - though ours seemed to have been dunked in olive oil before coming to the table.

There were a few dishes that worked. The roasted crostini - rustic bread gratinéed with mozzarella and draped with prosciutto - was addictive. The cream-stuffed burrata with cherry tomatoes was a step up from the standard mozzarella plates. A simple prosciutto panini, purchased from Serafina's take-out window, made a lovely lunch. And the Gnocchi di Mamma was surprisingly great, the tubes of potato dumplings defiantly tender against the pop of whole cherry tomatoes in sauce.

I say "surprising" only because the rest of the pastas were so lacking, whether it was the oddly pasty and dry Bolognese, the bland spinach ravioli in sage-butter sauce (that didn't taste of sage), or the lobster spaghetti, which looked like a wig of noodles on the plate threaded with chunks of half a lobster overcooked to rubber.

A special pan-seared branzino was cooked beyond recognition without the benefit of its skin to preserve its delicacy (to the dismay of Assaf, the menu's creator), then served plain with grilled artichokes and tomatoes that were hard and pink (yes, pink!) in August - for $27. A vitello Milanese was impressive in its plate-sized girth, the perfect roundness of its shape and even the tenderness of its meat. But its butter-soaked crust was so completely unseasoned that it wasted a perfectly good chop and what I'd hoped would be a savior of my second meal. (The chocolate "souffle," not really a souffle and microwaved to sogginess, wouldn't help, either.)

But even though I saw yet another patron have a tantrum, verbally abusing a food runner who got in his way, I finally felt comforted by Serafina's celebrity scene - for a moment. Sitting at the table next to us, demurely sawing away at her veal scaloppine al limone, was former District Attorney Lynne Abraham, who we all know doesn't brook bad behavior.

Then I felt another BUMP. BUMP. BUMP. A server had rammed my chair on his way to an ill-placed register, not once, not twice, but throughout the entire meal. My blood pressure started to rise. And then I remembered: "This is not the place to be if you don't want to be touched." It's not the place to be if you want a good meal, either.