MARIETTA, GA—Unbeknownst to attendees of Susan and Mel Gullicksen's holiday party Saturday, the Feather & Fennel Catering staff spent most of the evening mocking partygoers behind their backs.

Feather & Fennel staffers laugh at a partygoer's lime-green dress.

"Matt, you have got to see the sow in the powder-blue chiffon jumpsuit," said Feather & Fennel server Christine Salerno, 23, whispering to coworker Matt Blaine. "She looks like Brian Dennehy in drag, only less feminine."

Blaine then rushed a tray of miniature quiches into the living room to get an eyeful of the unattractive guest.

The party, held in the Gullicksens' spacious suburban Atlanta home, was attended by nearly 100 friends of the upper-class couple. The caterers were hired to set up the buffet, serve appetizers and entrees to guests, and break down the food area at the party's conclusion. All surreptitious, catty remarks about the Gullicksens and their friends were added free of charge.

"I've seen not one but two different people wearing pastel sweaters knotted around their necks," said Blaine, 20, during a cigarette break outside. "I think we accidentally stepped into a time machine set for Dipwadville, 1984."

Though no guest was spared, the caterers reserved their greatest scorn for "Jumpsuit Woman," "Chivas-and-7-Up Guy," and "Golfman," a fiftysomething gentleman with a bad combover who, Blaine said, "would not fucking shut up about golf."

Another guest was dubbed "The Vegetarian Avenger" because of his repeated complaints to the catering staff about the evening's lack of vegetarian options.

"He's at a friggin' Christmas party," Salerno said. "What does he expect, endless trays of bulghur burgers?"

According to Feather & Fennel staffers, a majority of the mockery was done covertly, with wisecracks delivered either in hushed tones or in the kitchen, safely out of earshot of partygoers. Caterers alerted each other to the presence of particularly ridicule-worthy individuals with subtle glances or quick jabs to the ribs.

But despite such discretion, on a handful of occasions, the caterers boldly insulted guests to their faces without them even noticing.

"One guy asked me if the roast beef we were serving was kosher," said Ron Essen, 22, whose sole job all evening was to carve slabs of meat for guests. "With a straight face, I told him it was a kosher roast beef flown in specially from Israel. Cynthia, one of the runners, overheard me and ran into the kitchen because she thought she was gonna lose it."

Another guest who received more than his fair share of furtive derision was "Five-Time Fatty," a heavily sweating man who returned to the buffet table five times in a half-hour span.

"The last time Five-Time Fatty loaded up his plate, I could see Matt making all these faces at me from across the room," said Salerno, who manned the buffet table's ziti station for much of the party. "But Five-Time was trying to chat me up, so I couldn't laugh. I knew Matt was praying that I'd bust up right in front of the guy."

While, traditionally, most partygoer-mocking is done during a party itself, Feather & Fennel staffers have been known to mock particularly memorable guests weeks or even months after an event.

"One guy at a bar mitzvah got so shitfaced, he passed out in a plate of kugel," Blaine said. "Ever since, whenever we see somebody who looks like he's about to pass out, we say, 'Uh-oh, better hide the kugel.' Man, that guy was seriously plowed."

Experts say mockery of the well-to-do by the serving class is a millennia-old tradition.

"Whenever people are forced to serve others, resentment and derision are inevitable," said Dr. Henry Janssen, a University of Georgia anthropologist. "This tradition dates back to Ancient Greece, where servants at grand Athenian feasts would sneak into the kitchen to put on short plays lampooning the foibles of their wealthy, gluttonous guests. As long as there are people who stuff their faces with mini-meatballs while wearing bad ties, there will be servers there to make fun of them."