I agree with you that the ENFJs have a shadow. Their shadow is what they don't tell others. What they omit from their conversations. Why they don't want to be alone. It's easier to drown out pain and suffering if you keep yourself busy with the problems of others, and pretend to wear your emotions on your sleeve. In reality, ENFJs (and I would argue ESFJs as well) have a well-developed inner world, but it is surprisingly dark. Darker than they allow others to see.
ENFJs and SFJs like to project themselves as being emotional, being able to be overcome by emotion, but only as an act for others, not for themselves. Fe to me is just that. It's being concerned with social niceties, not necessarily because one is "fake", but, just like all personality types, as a way of coping with reality.
I like what you're saying, but I'm going to have to say something about the social niceties thing that seems to inevitably come up when discussing Fe. IMO,
Socionics tends to have the least loaded language when describing functions and I really like this description of Fe. Extroverted Feeling as I experience is not merely about social niceties or being politically correct. It's about being thoughtful towards others and emotional expression.
extraverted ethics types pay close attention to the way people say things, the way they talk, their facial expressions, their choice of words, their gestures, and all other external manifestations of one's internal emotional state...They use their own expressiveness to guide other people's internal experiences and help them experience a wider range of passions and more intense feelings...extraverted ethics types like to discuss these passions and to analyze and discuss their own and others' feelings — not necessarily to change them, but more to bring them out in the open and understand them in order to base one's actions on one's true passions.
I think that if you have an ENFJ (and ESFJ) who hasn't cultivated their introverted functions (Ni/Si and Ti) to temper the Fe then yes you get a person who is overly concerned with the rules of social interaction and not the quality of the interaction itself and someone who is so overdramatic and stereotypically emotional they can't be tolerated for any extended amount of time. I know I tend to skew more towards the overdramatic than rule bound.
And it's a fine line between being impassioned and nucking futs. I know my nature and I try to work it to my advantage by being
entertaining with my theatrics, but I also watch to see how people are responding to me and if it's OK to kick it up a notch (I like doing that, it's fun

) or tone it down some. The big thing is that I'm watching to see how other people are reacting to me so I can modify my behavior accordingly. I'm not quite sure what you mean by it's an act for others? It's so funny, I guess when I interact with people quite often I think to myself, wow people are so bland and subdued and someone needs to change the atmosphere and lighten the mood. I do that for my benefit just as much as for others.
When I'm alone for too long (like weeks without meaningful social interaction), I begin to feel like my thoughts do go in a more negative direction I don't always care to explore. But that stuff doesn't just go away, it's still there and not thinking about it doesn't make it cease to exist. I do struggle with knowing how much I should delve into these thoughts (usually negative ones about myself, my abilities, my future, what I've effed up in my own life and how/if it can be fixed, and my relationships with people). So yes, if I know where my mind floats when it's allowed to roam freely without some outside anchor it can get bad. Left to my own devices, I tend to dwell on the more negative aspects of myself. All roads lead to Rome, so no matter where it goes I'm eventually going to have to deal with whatever is troubling me. When I don't want to deal with it, distracting myself with other people's problems, needs, and concerns is a nice substitution for dealing with my own. But above that, I do genuinely enjoy interacting with people and solving people problems so it's not all bait and switch.
Fe types tend toward the outer world as a way of rejecting the reality inside them, just as Fi types can sometimes forsake the outer world as a way to reject the reality that exists outside of them, which can leave us feeling dejected and alone at times.
The result is usually that Fe types can forget that they can be happy without projecting their emotions onto others, and all of their effort goes into projecting that happiness...
Yep. I was telling my boss recently how demotivated I feel at work and her first response was "you don't look like it."

I'm just not a sullen and gloomy looking person. Sometimes I am in a cheerful mood but just as often I don't want people asking questions I don't feel like answering so being cheerful is good deflection. And like what's been said already in the thread, most people don't really care to hear about your problems because they're dealing with their own. I can't be mad at people for that because sometimes life gets really real and it's all you can do to keep yourself and those you care about from drowning. It's interesting, sometimes I read on the forum about people's annoyance with some person coming up to them and spilling their guts or striking up a casual conversation. I think to myself when this happens to me, this person could be on the edge of a cliff and maybe I could be that conversation that keeps them from going insane, which is why I typically don't mind people talking to me and why I engage them. I just don't know what's going on in people's lives and to coldly brush them off is such a horrible thing to do in my mind. This tends to have mixed results, but for the most part isn't too intrusive. Maybe I'm projecting that people don't really care? I don't know if I should use the forum as a basis for what people really think but don't say publicly, but it seems to me that most people don't want to get into someone else they don't have a personal investment in that deeply. I have people I trust that I can talk to so I'm not too worried about not having outlets.