I may need to say something that is (seemingly) nice about someone, but I’d prefer it be very subtly backhanded or nearly believable hyperbole.
Edit: I realized that I was imagining something like how the Colbert Report was done where it’s easy to believe I’m agreeing when really I’m spoofing.
My experience is it’s used as “go fuck yourself” when it’s coming from strangers or people trying to place themselves as superior. In more familiar relationships, it can also can be used to express sympathy (especially about pain or difficult circumstances), as thanks, or to communicate you’ve misunderstood something (but it’s okay that you did).