All valid points, but what about hating without dwelling. I agree sitting in the corner of a room in the fetal position working yourself up into a lather is not the way to go. Will absolutely make you ill. But can't you just internally acknowledge that you hate this particular person, you have every right to hate this individual, and move on? I think the opposite would make me unwell. If there was someone that I dispised and I didn't allow myself to feel those emotions, THAT would make me sick. Literally.