I have always understood feels as only appropriate for emotions generated by fannish things.

Someone commented that they've seen people use it as a replacement for real-life feelings, and when I looked the "feels" tag on Tumblr I did see some of that, but that seems to be a kind of creeping of meaning to me. I suspect eventually it will transfer over to the larger world entirely, and then fans will have to find a NEW way to express roughly the same thing. :)

Kaonashi is one of my favorite characters--that might not be the best thing to say considering he's, well, kind of messed up, but he just...he has a lot of feels, okay? :)