Tally gets used to living in the Smoke, gets used to the work, and to cool showers, and no Twitter.
And she fits in well. In fact, David gives her some gloves as a present to protect her hands from all the hard labor.
The fact that Tally is more comfortable in the Smoke makes it more ironic that Croy has some serious suspicions about her. Like, if she was out so long in the wilderness, why did she have so much SpagBol left?
Tally makes up some lie about not eating all her recommended daily SpagBol meals, but his suspicion makes her nervous.
So when Shay is upset, Tally thinks it's about Croy's suspicions. In fact, Shay is upset because David gave his gloves to Tally instead of giving the gloves to her. (Not that she needs gloves, but the gift-giving clearly means he's into Tally instead of Shay.)
Shay wants Tally to tell David about whoever gave her the heart pendant and thinks that Tally is being a little shady coming here and stealing the guy she likes.
Welcome to future romantic triangles. They're a lot like the old ones.