Kyouko actually loves Yachiyo back
- Judging by her emotionally stunted behavior, Kyouko likely has trouble showing her true feelings in general, so showing affection for Yachiyo would be rather tough for her. Her only outlet is to have Yachiyo prepare food for her so she can hand out compliments.
- The main reason Kyouko (mostly) gave up her delinquent life style could even be that she could be with Yachiyo at the restaurant.
- Of course, her outcry of "Yachiyo is mine" should be as a rare indication about how she really feels.
- And Yachiyo herself might be aware of Kyouko's feelings, but knows she can't push the issue. Poor girl—she didn't find the easiest person to fall for.
- Furthermore, in the manga, volume 10, when she learns Satou's in love with Yachiyo she, unconsciously, takes a nailed bat and is seriously disturbed.
Alternatively, Kyouko's just Genre Savvy
- Since she knows that rebuffing Yachiyo can only end badly, she keeps up the charade to keep a hard worker and her belly full. Notice how she gets tired of Outo's treats just in time to save his life and says just the right words to keep her from killing him after Yamada's little Replacement Goldfish stunt.
- She speaks very formally. Seems a little confused about how to do simple house hold chores when she first came. She became completely enamored with a girl who carries a katana more or less on sight. She knows how to plant bugs and making convincing cover for people. Just seems like stuff that might have been taught a little yakuza girl.
- Jossed. Yamada's family eventually appeared in Chapter 188 of the manga. Her mother is a secretary and works together with Takanashi's older sister's ex-husband under Takanashi's mother. Her dad has passed away. Although considering that Takanashi's mother is a politician that is hinted to have regularly tasked Aoi's mother to spy on her political opponents, Aoi's abilities might not be that out of place after all.
Satou is Sanji
- Specifically a future Sanji, after the events of One Piece, transported to the world of Working!. Obviously, he's matured significantly and/or fallen head over heels for Yachiyo, considering he barely looks at other girls. Evidence: a) just look at him, b) they both smoke(though that may be a chef thing) c) on at least two occasions Satou seems rather skilled with his feat when kicking Soma for annoying him d) Satou's completely unfazed by all the weirdness that goes on at his place of work, and Sanji's seen weirder.
On Kyouko's eating the restaurant's food
- Eventually, we learn that Kyouko eats the restaurant's food because she can't afford food on her own. Unless shes' lying, it feels wrong to me that a MANAGER can't afford food. I mean yes, she's lazy, but the restaurant seems busy enough, and its not like her boss is breathing down her neck, seeing as he's bribing her with food. So then why can't she afford food? Maybe her "juniors", who seemed too happy to come to her aid, as well arriving rather quickly, are living with her. Now, a manager not being able to afford food and logging for just herself? Sketchy. But difficulty supporting food and lodging for (at least) three people on a manager's salary, with Japan's housing costs, becomes much more believeable.