I think this forum is severely lacking material on the theory which it's based on, so I figured I'd start this thread.
But rather than using solely abstract verbal descriptions to differentiate these two very different functions -- this thread is dedicated mostly to tangible, visual/verbal media-based examples or representations. Feel free to share your own examples. (:
Warning: This thread may have movie/show spoilers! Read at your own risk. ^^ Tho I'll try to minimize plot details and just focus on characters.
Best Boy vs Raven
: real-time, speculative, doubtful/questioning, re-interpretive, mentally spontaneous, modifying their understanding regularly.
: Beast Boy is one such character, who is constantly adapting/transforming himself (literally) to the situation, "going with the flow" and often making witty comments. Many of these properties are also shared with Se. His energy is dynamic (E) and engaged in a type of feedback cycle with outer happenings.
: Optimism, Resilience, Naivete, Energetic
Throughout the series, Beast Boy is a constant source of comic relief, amusement, but also absurd decisions, general naivete but also levity in the face of gravitas. Ne has a childish quality always about it (independent of age) that sees possibilities in everything and is animated toward experimenting with those hypotheticals.
: longstanding, speculative, suspicious, growing an understanding slowly through time with little spontaneity about "how the world" evolves/exists/flows.
: Raven is by contrast mysterious, ominous, but also no-bullshit. She's able to think of the world as "other-than-how-it-physically-is" (an N quality) but this alternate perception takes the form of a pretty stable or longstanding paradigm.
Raven is quick to anticipate, almost pessimistically, the outcomes that will emerge. While Beast Boy is equally quick, but in suggesting alternative options. To Ni, its less a game of speculation and "options" and far more a game of figuring out what "is" underneath.
Ni's focus isn't on branching endlessly into doubts and reinterpretations, but is narrow and fatalistic in its thinking. Ni users can become caught in a feeling of inevitability that exists to situations, without being able to fully loosen that grip and explore alternatives. In this way, Ni can be just as rigid as Si in its interpretation of "How the world works"
An Ne user may put forth a hypothetical to an Ni user, and the Ni user may think "seriously? that's the dumbest idea. that won't work" because Ni has run the situation through their worldview and found it incompatible with how reality unravels.