I commonly don't take Shai's stance and I end up getting taken advantage of due to that. In terms of both parties in this, neither is evil, it is just human nature. You give an inch, they take a mile. It has to do with maximizing the resources available. Yes, I consider social bonds as a resource. The idea is when you cannot support yourself, someone else will come in to help, and vica versa. At least, that is what I consider a friend and if they have proven that is not their ambition then I have no reason to be friends. There are people that I have entertaining passtimes with, but if they aren't there for me when shit hits the fan then they aren't a friend, merely an acquaintance with similar interests. Anyone that has an actual friendship with me knows that I am there if they call on me. Although in general I still isolate myself all the time unless you physically come and pull me out of my room, and even then I resist.
Some people don't understand the implicit 'best practices' of social structures as well as others.
Sometimes when you are down and out you will look for anyone to talk to, especially if the usual suspects are no where around. I have been there plenty, it is a tough spot and I would like to say I have learned from it but I seem to keep making the same mistakes over and over. (isolation)
However, there is no blame on Shai's end. You don't have to latch on to every single person that comes your way or might have been a potential romantic interest. She expressed she was not interested, both of them moved on. She never made any attempt to further any social bonds or show she cared for Shai at all, and now Shai laughs when she expects the exact opposite from him.
I personally think she was hoping there was still a hook in his mouth. But then again, I don't know her and I only have 1 side of the story.