I also feel like I should post the most liked comment because it was interesting:

"It probably started when she felt displeased that Miharu-san and Nozaki looked like they were having fun together... The reason why she doesn't seem to mind taking Nozaki around everyday is probably also because, ultimately, satisfying her own feelings comes first for her, while her partner's situation and feelings come second..."

"If Miharu-san's issue is her restraining her own feelings, and Nozaki's is his indecisiveness, then Oshiko's is probably her strong need for approval that doesn't take other people into account... I hope there's an opportunity for things to change (it doesn't seem like things will work out if they stay as they are now)."