A young man asked a girl hanging out in a beautiful afternoon after work. But she trotted away with an old man in his 40s to play Golf. Below is the article:
He remembered those weeks of timid indecision, during which he had looked and longed and despaired of ever having the courage to ask her.
Dared he face the risk of being humiliated by a contemptuous refusal?
But if she were to say yes, what rapture!
Well, now she had said it and he was still wretched–wretched that she should have thought it such a perfect afternoon for Obstacle Golf, that she should have trotted away to join Henry Foster, that she should have found him funny for not wanting to talk of their most private affairs in public.
Here are 3 "should have done", but the things had happened, not an assumption. In the Chinese translation, it "should have done" express the boy unexpected / surprised those things and thought it was not fair.
I looked up this What are all possible usages of “Should have done”, seems not one mentioned this useage of "should have done".