What are emotions? Well, according to a book I just read, Crucial Conversations, they are the result of the stories we tell ourselves.
Those stories being subjective, the emotions, too, are subjective--and subject to change. But don't try to tell someone who felt bitter disappointment that it wasn't real, just because the story upon which the feeling was based wasn't.
Wasn't real, that, is.
I just saw an article for this: https://www.affectiva.com over at Slashdot (https://developers.slashdot.org/story/17/05/21/2137208/how-ai-can-infer-...).
Of course, using a massive database with humans providing the context, machines can learn, but can not understand.
Thus, they can't explain their decisions, or help emotional cognition, just recognition.