If I would assume Hachiman’s thought-process based on the events he just experienced, the question: “What does this girl need from me?” must’ve been the biggest of his concerns. No matter what the occasion, a pretty girl like Yui can’t be kind to someone without a reason.
Reinforced by the fact that Hachiman does emit a strong unsociable aura, he must’ve misunderstood Yui’s intentions as a form of self-imposed guilt trip. In a way, she owes Hachiman for saving her dog. Whether she likes it or not, as a human being, she is bound to pay him back, one way or another. And being the miserable existence that Hachiman is, this is the perfect way for her to clear her debts and end her guilt… so as I interpret it.
Despite introducing Kawasaki Saki, I believe that the core plot of this episode was a deeper understanding of Hachiman’s personality. We have seen his guts on the previous episodes, his sarcasm and wit, but this defeatist attitude of his is the glimmer that appeals to me strongly. I wonder how things would proceed between him and Yui from now on. After all that’s been said and done, what lies for our protagonists?