Rich Guy
A character refers to Mr. Grassly with a humorous metaphorical image. "That guy burps money in his sleep." This assessment of Grassly occurs early in the story and so very quickly situates the primary characteristic of the man. The metaphor is referencing the way it seems that Grassly is able to accumulate wealth so easily as if he doesn't even need to try.
Empathy
The story revolves around a father desperately trying to raise money to buy a gift for his son. Oddly enough, he refuses to accept financial aid from his boss right at the start even though his boss says, "You're in luck. I've got a heart and you're breaking it right now." The metaphor of the broken heart strongly suggests that the boss is actually empathetic about the father's plight. Despite this, the father rejects the offer as one made out of charity stimulated by pity.
Marcus
Marcus is an altogether unpleasant character. He is ugly on the outside and the inside. At one point, the protagonist turns to Marcus and says, "You're a monster." To call someone a monster is a very common metaphor for a person who seems less than human. Since at this point Marcus has attempted to kill a living cardboard man, it is almost literal rather than entirely figurative.
Plato
The cardboard is not killed, however. In fact, when he recovers from the injury done by Marcus, he becomes better than ever. He even starts reading and quoting ancient Greek philosophy. "If a man neglects his education, he walks lame to the end of his life." The metaphor here is directly connected to the resurrection of the cardboard man after his near-fatal experience. He arrives at self-awareness and tries to improve himself so that he is a fully complete and functioning being.
Single Male Behavior
A single female neighbor seems to be romantically interested in the father and so is more than willing to watch out for his son whenever he has to be away. She immediately notices that two males living without female influence in the house are rich in metaphorical comparison. "You men live like complete animals." This observation is made specifically in reference to an oven burner which has gone far too long without cleaning. The comparison to animal-like behavior also references the fact that the dad cannot even make macaroni and cheese without causing a mess.
