"I did Nie Huaisang's math homework and in exchange he gave me a candy!" He hands it to her. "So even if the vending machine is suspicious you'll get something to eat."

She has a candy! No one's given her candy before! Let alone in a context where candy is super valuable! "Thank you so much!"

"I probably would have done it for free but don't tell him that."

"A man's got to keep some of his secrets."

Walk walk walk to the vending machine. "Is it good? I haven't had one yet."

"It's delicious." Oh no, she's deprived him of candy.

"I've been saving up my vending machine tokens so I can probably get you something minimally dubious. And you can cheat it to kill the microbes."

"You don't have to, I wouldn't want to impose." ...even if this is a date.

"You're doing me a favor, if I don't get to give presents to pretty girls I'm going to become horribly depressed and throw myself in front of a mal."

...well, that's definitely no expectations on her shoulders. "Okay!"

"Oh, don't make that face, si-mei, it's a joke."

"Oh. That's good. --Sorry."

"Between us, si-mei, there's no need for 'thank you' or 'I'm sorry.'"

"But what if I want to say 'thank you'?"

He starts singing something very catchy in English.

He continues to have a very charming singing voice that is very good at making her turn bright red.

"Oh, wait, that joke doesn't work because you don't speak English."

"I speak a bit but-- not enough to follow songs."

"It's 'You're Welcome' from Moana. --We watched a ton of Disney when we were little, to motivate us to learn English."

"That's cute!" She is totally picturing a tiny Wei Wuxian watching Disney now.

"We had a singoff with New York the other day, I don't know if you're close enough to Wen Ning's room to have heard it--"

"Oh, so that's what it was. I heard distant singing, but not what it was."

"Showtunes!"

"Which is much better than a yelling argument."

"Do you know Disney?"