I notice that even when people are fighting and whatever negative things come that way, I feel a sense of pleasure in logical argument. It tickles me.
I also noticed that when talking to ISFjs or ESFps, if I show genuine affectation (is that a word?) they seem to get what seems to me as perverse pleasure from seeing my emotions affected on a deep level, which I think because I am showing negative emotion. It occured to me that I might appear to be a sick bastard as well when I am gleefully smiling at some logical death match, right or wrong.