Extroversion focuses on objects i.e. the things themselves. Introversion focuses on fields i.e. the relations between people and things.
As such, an Fi is about one's feeling towards things i.e. Do I like this? Do I like that? Does this person feel happy about that other person?
Fe on the other hand is about the emotions themselves... What is the mood of the room? How should people be feeling? What am I doing to change how they feel?
I'm trying understand what you are getting at by wondering what good even means. This does not sound like Fi though, indeed I wonder about this myself quite often. Usually Fi does not really focus on trying to make sense of feelings, the feelings are just felt and take priority over any logical order. It is common for a Ti type to insist on feeling making some sort of sense, hence wondering about meaning and either coming up with a concise definition or discarding it as meaningless.
Both kinds of Ethics (Feeling) are seen as 'Internal' rather than 'External'. They are judgements that come from within rather than being sourced from the outside world. Ethics only really exists in our heads.
For an Fi-lead though, everything that draws their attention is judged by Fi. For an Fi type with creative Ne, it will be a lot more Internal, judging ideals and concepts within the mind (Ne) more often than real, concrete things in the outside world (Se). Indeed Intuition is also Internal while Sensation is External.