I guess I'll start with being glad to see Chiyo and Igarashi getting along and that, despite Chiyo's grumpiness, they are taking a class together. The class itself makes me wonder if Coco, herself, had a teacher like that. Pretty odd when you think about it.
It's also always good to see Subaru-chan! If only Chiyo wasn't there, she would certainly make a good mate for Igarahsi. Pretty, sweet, kind, and, unlike Chiyo, treats Igarashi like the nice guy that he is.
Now to the dark side. Chiyo and Kitamoto apparently haven't learned their lesson from the Miyako incident. They immediately jump to conclusions and think the worst of Igarashi, having no faith and trust in him. Of course there's a reason why Chiyo does not trust Igarashi: she, herself, cannot be trusted as she is not honest with him.
Of course, Chiyo is also two-faced. It's not okay for Igarashi to talk to another woman, but she can talk with whatever man she wants. She's had private, intimate conversations with Ryouhei, Ookuma, and Kitamoto, but if Igarashi even looks at another woman he's cheating on her. How ironic that, in practically the same breath that she is bad-mouthing her boyfriend for talking with another woman, she is running off with another man.