Yeah, they behave differently to some degree, the effect of having lower priorities in the psyche, and/or being offside functions. I have tried to understand what it must be like, but I can only do it in the abstract. But to be honest, I have been in the grip before, I have experienced what it is like to have really over sensitive Fe and start interpreting things to be potentially offensive slights against Fe. It's still an inferior function experience, but it still get's pretty intense.
With dominant Fe, it becomes something personal and intimate. Like the person actually has their face pressed up against the glass of the Fe world. The rules of Fe become more like law, and to slight a person through a misstep in etiquette is a much more personal offense. Like with INFJs, they are aware of it, and they are even involved in it at times, yet they are still detached and from the inside looking out. You know I never really saw Fe as meek to begin with just because of how powerful it can be even when properly utilized as an Inferior. But yeah, Fe is actually a lot like Te if you have not already have had that thought. They are both used for manipulating and moving the dynamics of an external construct, a social and cultural construct vs a systemic construct. There is still a "This is the way we do things around here!" kind of enforcement that you get with dominant Fe that is very similar to the kind you get with dominant Te. Yeah, I have experienced dominant Fe get pretty bad at times, it can be pretty thunderous as well as harmonious. But Auxiliary Fe is not really free of this either, it just expresses a different kind of anger from having a different top priority. Fe doms get angry a lot, and then quickly shift moods. INFJs, they don't get angry often, but when they do it is scary as hell. Waaaaaay scarier than the ENFJs.
I actually made a new ENFJ friend somewhat recently. It was kind of funny, because he kept doing things expecting to get a reaction out of me (As Fe doms usually do), and then he would get mad at me for not giving him one. Like he would say a joke, but I didn't realize he was joking, so I would be sitting there analyzing what he said, and then he goes... "Fuck you then!" Another friend later said he needs to drop the ego if he thinks everyone is supposed to laugh at his jokes. To which I replied "It is not so much that he has a big Ego, it is just that in Fe land, it is proper to laugh at one's jokes even if it is not even funny, just so they don't look stupid, and he was a bit insulted that we didn't follow protocol."
One thing I noticed is the highs of keeping group harmony are much higher, as well as the lows. Like if they go out of their way to do something for you and you validated them for it, or better yet if you go out of your way to do something for them, then the feeling from this will be all the more intense. Likewise if they are slighted in someway, the insult will be all the more intense.