MetricalNoir, INTJI've always felt that I'm good at 'reading people.' I study people and their reactions to circumstances, and believe that I can gauge their emotions once I know them well enough. However, I'm no INFJ, so I cannot 'feel' emotions that others are feeling, and generally respond to situations depending on what mood I am in at the time. If I'm neutral, I view everyone else neutrally; if I'm stressed, I'm more likely to notice that others are stressed. I do however enjoy studying facial expressions and seeing if I can figure out their emotions that way.
Oh, and I can always tell when a person is being phony or unfriendly. Gah, phony people might be the death of me if I actually allowed myself to dwell on them. Thankfully I surround myself with very real and non-phony persons, so I don't have to worry about that. It just strikes me as extremely odd whenever I walk past a person who I never speak to, and that person will greet me with a cheerful 'hello.' Most times I'm so shocked that I'm unable to respond and simply go past trying to pretend I hadn't heard. I like being friendly... but only to those who appreciate my being friendly. Like most INTJs, I'm sure, I don't understand those people who are friendly to everyone, even those they seem to dislike (such as myself).