I have tendency to give more to people than they give to me. (Keep in mind, this is only people close to me. I do not particularly invest my time in people that I don't know well.)
But it's a pretty typical human thing to care a lot about the people close to you and not much about people you don't know. That's one of the things that makes typing tricky: it's not a checklist of things you fulfill, it's a system that explains things working together in your personality. Two exactly similar actions can have two completely different typology implications.
So in separating the wheat from the chaff, the question becomes how those actions are important to you.
For me, I give to others and am kind to others because I consider it a moral imperative to make the world a better place for my being there. I believe that it's me being a conscientious world citizen to do that, and fulfilling my personal ideal and mission to care about others. It makes me a happier person, it fulfills me emotionally, and it satisfies my personal ideals. That's all Fi.
On the other hand, I have friends who believe in helping others because they want to be useful, or to express their happiness and kindness towards others. Their motivation is in the act itself, not on a deeper, more personal level. That would be Fe.
To simplify that a bit, I make people happy because it makes me happy. There's an intrinsic, ideological component driving it (and is part of why I like Ayn Rand's defense of selfishness). My friends give to others because they want to give to others. You can even (albeit a bit inaccurately) break it down to extrinsic and intrinsic motivation. I'm my own reason for helping others, no matter if it's noticed or appreciated, because I'm operating with Fi. if I were operating with Fe, the consequence of my actions would matter. Was it helpful? Was it not quite right? Did it get the result I wanted? Has it caused the change it was intended to cause? With Fi, I don't care if the person appreciated it or changed because of it. I did what I needed to do for myself.
Could be lack of personal boundaries (a hallmark of Perceivers) along with an Fi value that says you should help out those around you. That combination turns lots of INFPs into doormats for the people immediately around them.
This.
I didn't even notice I was doing this until my ENTJ adviser in college pointed it out to me. I was in her office, and the janitor came to collect her trash. I never want to feel like I'm stepping on a janitor, so I offered to carry the trash can out into the hallway for her.
My adviser pointed out that this is implying she can't do the job herself, and that I have no business carrying an actual trash can for someone. I didn't feel like a doormat, but it also made me realize that there's reasonable limits to what I can or should do for others, and that carrying a trashcan for someone whose job is to literally empty trash cans is one of them.
Also, FWIW, Fi-Doms are often good at Fe (which may be another way of saying what I just said above), and Fe-Doms are often pretty good at understanding Fi. The introverted and extroverted variants of each function are close enough in essence that we often become reasonably good at both over time.
I agree, but it's tricky. You have to invest a lot of time and soul-searching to distinguish between the two, because they overlap so much. At the same time, it's worth the effort, both personally and as far as understanding Typology better. It especially has implications when you start getting into Shadow functions (if you get there, I've been in MBTI for over 5 years and just got seriously interested in it).