There were many things that were handled a lot better in the manga, like Tsukasa confronting the annoying girls in the class. Moreover, this anime goes to show that the staff has something against kissing. But well, that's nothing to be surprised at this point, although, I've got to admit that, especially in Tsukasa's case, it made things much, much sweeter.

Either way, comparisons aside, for what concerns Tsukasa's development, this episode was, perhaps, the most important. She started taking care of certain issues regarding her own personality, on how she decides to deal with others.

After the falling out with her classmates, their manpower to complete the Christmas event preparations are considerably diminished.

Ayatsuji forces herself to work over time to finish things. Kouichi is worried about her health.
He suggests that maybe it's better to ask everyone's help again.

Ayatsuji gives him the "what? are you serious?" look

Kouichi tells her that they won't complete the event at this rate.

Ayatsuji tells him that they have 5 people working on this, don't they?

Koichi says that Ayatsuji is overexerting herself and there's not enough manpower to finish the project
even with Kaoru, Keiko and his friend helping.

Ayatsuji tells him that if that happens she'll push on and get things done

Kouichi tells her that she's going to collapse again at that rate

But Ayatsuji still doesn't like the idea and tells him to drop the subject

Kouichi says Ayatsuji is acting strange and not being herself. Koichi says that Ayatsuji was not like this.
She was a problem solver that managed to get things done and not held back by personal feelings.

Ayatsuji SNAPS. She asks what exactly does he mean by that?

Kouchi says he understands. He knows that she is working hard for her future.
Kouichi recommends either one of the following:

1) Apologize and mend relationships with the other girls earlier. Ask for their assistance again.
2) Take it easy and prioritize her health. She has already collapsed several times, mind you.

SLAP

Ayatsuji snaps at Kouichi. She is sad that why he is able to say these things even knowing why she works so hard. She runs away in tears.

The next day we see Ayatsuji being nice again with the girl who harassed her. We learn that Ayatsuji has apologized and used her role model persona to mend relationships. But you can sense that something is very wrong.

Koichi later confronts Ayatsuji and asks her what happened to her. Ayatsuji says that her other self that lashed out at people is now gone. She is now wearing the role model student persona forever. She refers to that personality in third person.

This episode is appropriately titled "Pride"

We see Kouichi being worried about Ayatsuji's health, but forgetting the hidden pride concealed within. His intention was well, but a few careless choices of words lead her to believe that the role model persona was the only persona that was accepted.

Telling her that she was not being herself probably has the side effect of making her taking it literally. Who is Ayatsuji really? The unfortunate answer that came out of this was to abandon her sense of self and fully adopt the model student persona.

If you have played Persona 4, this episode is really a lot like that.

The Ayatsuji that lashed out is the Id. It is her Shadow.
But instead of reconciling her Superego and her Id, Kouichi made her do the opposite and cut off her repressed self. Now only the Superego is dominant.

Next episode preview seems to emphasize this conflict.

Kouchi: Where did the Ayatsuji that I love go to?
Ayatsuji: but I am me. I am me.

This is not about merely swallowing pride. Junichi killed the "inner Ayatsuji" personality. Seriously, he doesn't even realize what he did.

First, he uncovered Ayatsuji's hidden side
Then, he encouraged her to be more genuine
Then, she opened up to him and decided to trust him
And then, after all this, he cut off her hidden side at the neck, when he chewed her out and told her to apologize to the triple bitches.

This is why she ran away in tears. Essentially, he drew her hidden side out, she trusted and confessed, and then he denied her. And she couldn't deal with it. And killed her hidden side. At the end of ep23, her "outer shell" has taken over. She said it herself - "this girl doesn't exist anymore".

Someone made this rumor: Since Eureka, Kaori Nazuka's anime role is guaranteed to break. I didn't know it's true.....