For me, I think my Fe is really simple. It's all about "the team". Of course, it depends on the individual and the situation what the team includes. Sometimes it's just two people. Sometimes it's the whole human race. The basic principle is always the same:
what works for us is what is right.
I'm in a relationship with an Fi-dom and I've started to be able to sense what Fe is from how I'm different from him. Sometimes it is fascinating to see how what I thought 'everybody knew' was a completely foreign concept for my INFP. The same thing goes vice-versa, of course.
Based on the single principle of
what works for us, I've noticed a few manifestations of Fe:
Open Negotiation
This sounds like Te, and in a way it is like Te. Whether you have had experience with the people-pleaser Fe-user or the annoying self-righteous Fe-user, you'll be surprised how much they are willing to openly 'negotiate' things with you (even almost objectively). "Can you please not do this because it makes me feel uncomfortable" is a very reasonable request and most Fe-users will not take offense. However, here is the tricky part: because Fe-users are so attuned to other people's emotional states, most of the time your delivery of the request will matter a lot, which leads us to the second feature of Fe:
Cues
Fe-users live in a world of cues. It's unconscious. We are not trying to make your life difficult. It is just so natural that sometimes we are not even aware of the fact that we pick up and interpret so many emotional cues from other people
all the time. So what are these cues? They can be anything: facial expression, tone of voice, action, choice of word -- basically everything you do. Fe-users feel themselves part of a whole, so they try to constantly gauge the team's emotional state to see if they need to make adjustments or to do anything to keep the team happy. This means they are on a constant lookout for 'cues' or 'clues' from other people and try to guess the meaning behind these clues. Because they are so sensitive to picking up cues, they assume that other people will be as sensitive, so sometimes instead of making direct requests, they drop subtle clues about what is making them unhappy and would like you to change. This is to let you know without making you feel accused of being insensitive. However, if you do not pick up the clues and try to do something about it, Fe will start to get hurt and upset and will start to act like wounded Fe and make your life difficult.
The So-Called Fe Rules
People talk all the time about Fi values, which are sometimes invisible. Fe values are just the same, except that they are out in the open. Since they are out in the open, and since Fe-users are mostly concerned about the team's well-being, these 'values' become 'everyone's values' and can feel like rigid 'rules' to non-Fe-users. Fe users tend to have 'shared values'. Most of the time they are the exact same values that Fi-users have. While Fi goes by "my personal values are part of me", Fe says "I am part of a whole, so these universal values are part of me".
So I guess that's it for the technical bit. The question is, what does Fe feel like for me?
For me, I usually feel an emotional connection with everything else. Sometimes when my Fe is in bliss, I feel a glowing warmth in me and I can almost feel the Earth's collective memory -- sad and happy and at peace, wise and watching. I feel a part of the world, and I feel I really belong here, because what I feel in my heart is the same thing that is felt everywhere, in every human and mammal and tree and blade of grass. I feel an acute awareness of everything else, of their presence, somewhere out there, and I can reach out and touch them. I rejoice in my place in the universe. Whatever emotions I feel, I am part of a greater existence, like a thread in a great piece of tapestry, and there are similar threads out there that resonate with the same emotions, and I can feel them all and love them all.
Wait... I think that's not really Fe... but oh well