Si is my absolute least preferred function, at least in models like Beebee's, even lower than Fe. Reminiscing can sometimes bring on a very unpleasant sensation that I have described as temporal vertigo. My memories of many things and times are fuzzy, especially if the events were not significant in some way. Pressing to get more clarity can lead to this.
Visible use of my Si is pretty negative, and positive use isn't really that visible because it's, well, introverted. But when it's visible, it's visible through pessimistic Ne projections:
"I'm never going to get anywhere.
What have I done with my life?
Every time I get ahead, I am sucked right back.
I give up.
I'll just keep this shitty job and live this basic life just like everyone else."
Many people think I'm IxFP or xNFJ, but there are better ways of measuring these things than anything currently in the Jungian/M-B communities.
NFJ is Tribe over Self, and I think it's obvious I'm self over tribe. This is heightened in me because I am a 4.
My struggle is in Chaos vs Order, as seen in those on the sensing/intuition axis. My yearning is for more, more, more; new, new, new; better, better, better, and the thought of never getting there and submitting to societal order kills me. So, at my lowest, I give in to Order (Si) but in a very one-sided, negative, defeatist sorta way.
Conversely, I'm relatively balanced in Self vs Tribe, in the sense that I don't obsess or struggle excessively with
not fitting in somewhere as you see with INFPs and ENFJs.
Examples:
*long ENFJ Facebook post about the stresses of being a good mother, wife, friend, neighbor, employee, and constantly feeling overextended and not good enough, but "this is my beautiful messy life and I wouldn't change it for anything"*
*INFP rant about "what do you want me to do? I'm going through a lot right now and I shouldn't be expected to live up to these ridiculously high standards in this moment".
I was gonna save this resource for myself selfishly (hello 5), but I decided it'd be significantly less annoying to have more people better understanding this stuff from a consistent perspective:
I'm still working through it all myself, so I'm no pro, but the above is my current understanding of it (basically a "subject to change" disclaimer).