Most of the movie builds up two things: Mitch, a waiter on his first day at work at Shenannigans, not being able to get in a word edgewise and the "Penis Showing Game" that keeps the male staff (mostly the cooks) from getting too bored at work. The ultimate play in this game is the Goat, a complex move involving tucking the junk behind the legs and bending over in a combination mooning and genital exposition. The most important part of the game is catching the opponent by surprise. In the climax of the movie - a house party - Mitch sheds his status as The Speechless and descends into one of the best renditions of "The Reason You Suck" Speech ever. After verbally ripping everyone who has insulted, degraded or rudely ignored him a new hole, Mitch declares, "Fuck this; I quit." Before he exits, though, he turns around and points to someone in the back of the room that he hardly had any contact with all day. "And you. You are the biggest piece of shit in this entire restaurant, and I hope you burn in Hell." This causes everyone to look at him wondering what he did, while he whips his head from side to side, wondering what he did. When everyone looks back at Mitch, there it is. The Goat. The first time playing the game everyone has been playing for years, and he executes a master stroke. On the entire party.
"Don't fuck with people who handle your food." After listening to the psycho bitch rant about literally everything (including bringing her food too fast.) Watching them get their long elaborate revenge is downright refreshing. If you've ever worked in a restaurant and dealt with similar Customers From Hell, you'll have to fight the urge to cheer.