IMO, I think you can line it in parallel with Te and Ti to help understand...
Both Ti and Fi are "idealistic" thought processes concerned with the integrity of the principles that underlie the way we live and make decisions. For Ti, this means ensuring that the underlying logic we rely on is airtight - sort of like checking an engine to make sure everything is in place, connected correctly, at working at maximum. For Fi, this means ensuring that the underlying value structure we rely on is airtight. That makes both Ti and Fi users more laid-back, as they are mostly inspecting and fine tuning, rather than directing F or T in a situation, but it also makes us more stubborn because our logic/value structures don't adapt to fit the situation - rather, they underlie every situation. It also makes us more perfectionistic in F/T judgments - we will be more likely to forgo an efficient solution for the sake of one that is more "right" logically or ethically.
In contrast, Te and Fe are "pragmatic" thought processes concerned with the manipulation of the environment to optimize conditions. For Te, this means logically reordering the environment (think the "logistics" commercials!) to create maximal efficiency. For Fe, it's a little harder to explain (at least for this Fi aux), but it's like a reorganization of the situation - often via impacting people and relationships - to create maximal fluidity (often harmony, but not always). This makes Te and Fe users play a more active role in their environment, as compared to more passive Ti/Fi users, but it also makes them less stubborn in terms of absolute logic/values, as they are more interested in the real-world effects and outcome than the static conceptual principles. (See why Ps are more air-headed? They are often more concerned with what should be than what is). This also makes Js more flexible in terms of judgments - where a Fi/Ti user is more likely to hardline, a Fe/Te user may be willing to sacrifice some of the rigid principles for the sake of better efficiency or better harmony.
In terms of how these play out IRL, because Fi users are more concerned with the underlying structure, they can access that through themselves, so they don't have as much of a drive to reach out to others unless there is a specific reason as guided by the underlying structure (eg, this person looks sad; it is good to help people who are unhappy; I should try to help that person). Like [MENTION=5418]Lady X[/MENTION] said, there is a fairly strong perception that our individual states of being are somewhat self-contained and independent, even though we may be affected by the same environmental variables - whereas with Fe there seems to be more of an awareness of those environmental variables and how they are impacting everyone, and a more clear perception of the constant influence that each person exerts on every other person. Because Fe users use those parameters of the given situation to make judgments, they have more of a drive to reach out to others, as it gives them more information about the situation and therefore helps them make better judgments.
In terms of making judgments, let's take a situation where a coworker makes a racist comment. While this may be impacted by MBTI type, Enneatype, and variant as well, it may still be that a Fi user may be more likely to call that person out on the spot, as they violated the structural principle of «racism is harmful», and there is a desire to correct that situation as soon as possible - if we don't call them out right away, that is tacit approval of their viewpoint, and it can encourage others to be okay with that viewpoint too, which is creating further harm. On the downside, the Fi user isn't as well aware of the cause/effect of their actions and doesn't necessarily act with the realistic final outcome in mind - rather, we tend to focus on the idealistic outcome, assuming that if we act "correctly", the situation will inherently right itself.
On the other hand, A Fe user may be more likely to pull that person aside later and speak to them privately, as the Fe user sees that calling them on the spot could make it a painfully awkward situation for anyone around, and it also might make the coworker less likely to be open to reconsidering their racist perspective. You might also notice a Fe user become visibly "cold" when someone has been offensive - it's almost a method of quiet operant conditioning / behavior modification, geared towards encouraging the right behaviors. On the downside, of course, Fe is not as geared towards the ideal.
Down the road, the Fe user might be more likely to avoid choosing that coworker for something based on this prior behavior - again, Je is more cause/effect oriented, and so in tandem with Pi can anticipate and manipulate future outcomes via gathered knowledge. Fi with Pe is more oriented to creating a structure that will allow you to respond well in any situation, rather than preemptively acting to create a better environment. Therein lies the foundational difference between Js and Ps... Js try to influence their outward environment while Ps try to influence their inward environment to respond in an effective way to their outward environment. Both have their pluses and minuses!
That is my current understanding, anyway!