I really enjoy comparing how the series has changed their character dynamic over time. Yamada always has her guard up around male characters as she has been shown to receive quite a bit of unwanted attention, like Pickup Senpai or the other boys in class. Factor in being a model, she’s implied to attract attention outside of school too.
In the first chapter, when she catches Ichikawa looking at her, her expression becomes serious and disinterested. In chapter 45 she glares at Ichikawa when she doesn’t recognize him with his face mask and thinks he’s some stranger approaching her. Before breaking out into a huge smile when she realizes it’s him.
She initially treats Ichikawa as a lackey, then a friend, then a crush before she falls head over heels. She gets jealous that Ichikawa calls her mother cute rather than her, and she cries when Ichikawa avoids her when he gets mad.