How do you make use of your inferior function, Fi?
Good question, I am curious as well.Could you say any more about your Fi use though?
I feel that as an ISTJ, Fi is a huge part of my character. (Unless of course my yearning to be authentic and my desire to live by my moral/ethical standards come from elsewhere than Fi, and I am mistaken). Though as an ISTJ I would still have problems with being really perceptive about other people's emotions, for example, so maybe my Fi isn't fully developed.
Another question: How do you ESTJs use your Ne? (I don't know how to use mine. . . it's probably just used for evil. . . my inferior function).
Unless you are attacking our moral character or something that we have accomplished, we don't tend to take things personally. We find it disrespectful when people waste our time, but I don' tthink that's considered hurting our feelings. I guess the closest to Fi I get is when I'm passionate about a topic I'm arguing over, but that's just for the sense of accomplishment. Do my accomplishments effect my Fi? I suppose in a way, I mean, I'm proud of myself, but if I don't achieve something, I'll just work harder next time. I don't think drive is the same as Fi.