The emotional should is the only model of the Subjunctive mood that is used not to represent an action as something imaginary or desired but to show the emotional attitude of the speaker to some real fact.

To think that somebody should care for such an awful man!
Только подумать, что кто-то способен любить такого ужасного человека!

It is strange that they should discuss such questions in the presence of the children.
Странно, что они обсуждают такие вопросы в присутствии детей.

It is wonderful that I should have met you today.
Как чудесно, что я встретил вас сегодня.

The emotional should can be followed by the Perfect Infinitive to show that the action refers to the past.

I was in conservatory when who should come but Captain Brown.
Я был в оранжерее, когда вошел никто иной как C.B.

The emotional should can express all kinds of emotions, both positive and negative – astonishment, joy, delight, condemnation, etc.