Playing With: They Wasted a Perfectly Good Sandwich
Basic Trope: A character orders food, which they then walk away from without eating.
Straight: Alice and Bob are in a restaurant. Bob's delicious sandwich arrives, and then the plot demands that they leave.
There is a Running Gag that every time Bob is handed an item of food, he's called away urgently and throws it in the trash.
Bob orders an expensive 3-course meal at a fancy restaurant and leaves before he can eat anything.
Downplayed: Bob orders small fries, but has to run out when he's only had a few.
Bob has an eating disorder, and hides it by making arrangements to eat in public and being called away "unexpectedly".
The interruption was really important.
The sandwich sprouts legs and forgets Bob to go on an adventure in a shocking BLAM... or turns out to be a MacGuffin that Alice and Bob cannot ever forget.
The Five-Man Band order something so they can enter the restaurant while waiting for a contact to arrive, and when nothing happens, they eat what they've ordered. Just after, the contact arrives.
Bob turns around and grabs the sandwich as he's leaving.
"Fuck off, I'm on lunch."
The characters have their plot relevant conversation over plates of untouched food. Eventually, Bob smiles and says "Anyway, enough business. Our food is getting cold here!" They tuck in, and the camera cuts away.
Parodied: Bob keeps going to take a bite of his sandwich, but each time, someone interrupts him with a question. He gets increasingly frustrated, especially since nobody else is eating their own food.
Zig Zagged: Bob orders a sandwich, but some plot happens outside and he runs out before the sandwich is given to him. The plot is quickly resolved, though, so he walks back in and gets his sandwich. As he sits down, Alice walks in, and the two have an extended conversation, without Bob ever touching his sandwich. Finally, the conversation dies down. Bob is about to take a bite out of his sandwich, until more plot happens outside. Alice and Bob run out, but Bob takes his sandwich with him. Later that evening, he walks into his house, plops a paper bag on the table and sits down — he's still got it with him. He takes a bite... "Goddamnit, I said no mayo."
Averted: Alice and Bob have a conversation in a restaurant, eating as they chat, like normal people.
Enforced: They're filming the conversation from three different angles and the actors keep flubbing their lines, so they're told not to eat anything to make it easier to shoot and edit the scene.
"It's not like I'm going to be forced to drop everything to go on some epic quest." Bob bites into sandwich, and epic quest ensues.
Charlie, the diner's owner sees Bob running out and comments "Again? Must be something important." and orders his staff to preserve it for when he returns.
Bob: "Whenever we go into one of those places, I end up without my money or my sandwich!" Alice: "Eat faster."
Conversed: "Why do they always leave perfectly good food behind on this show?"
Plotted A Good Waste: There is a theme of Conspicuous Consumption and the wastefulness of middle-class culture running through the work. If you watch closely, whenever they leave the restaurant you can see the waiter in the background clearing away their untouched food with a disgusted expression on his face.