On the experience of Before Midnight, and very little about the film.
With the advent of the mass availability of every film ever at our fingertips at any time, the old phenomenon of the long-sought-after film has nearly vanished completely, becoming relegated to more and more obscure films and filmmakers from smaller and smaller countries. Adding to this, the availability of writing on so many films with a simple search can serve to demystify unseen films, further peeling back the allure of the unseen mystery. It makes some sense, then, in a silly psychological affront to the usefulness of art, that new films can take on so much importance in the minds of people who have so many great films yet unseen but devote such a disproportionate amount to new films that would never have interested them had they learned of their existence years after their release as opposed to years before. In this sense, the long-hoped-for-and-some-would-say-inevitable-but-no-promises-were-ever-made Before Midnight sits at the top of the pile, as it was new, its future existence was never sure but long contemplated, and it actually had a precedent upon which one could expect not just another commodity of the same type but a deepening of a previous experience. In this way, Before Midnight is essentially the pinnacle of the filesharing era's version of the 'long-sought-after film'. You may know my great love of Before Sunset, which to me is miles above the first, which meant that the trajectory implied promising things which were actually probably impossible in all physical, psychological, metaphysical, and magical realms, so this was a pretty exciting event. However, given my active disdain for the aforementioned phenomenon, I may have a psychological block (or balancing mechanism, however you want to contextualize it) against making this the end-all-be-all of events. While the 'event' phenomenon of older films may largely be gone, replaced by an 'at my leisure' mode of engagement, I still make an effort to align my anticipation of films with the expectation of quality as opposed to the fundamental capitalist mechanism of scarcity, which seems to drive the other impulse. Long story short, I was greatly excited for the film, not just its newness, but probably not to the same extent as someone overly excited about newness in and of itself.
Of course, the long-anticipated event is the story of Before Sunset, not Before Midnight. In many ways, Before Sunset is special because of its premise, a different variation of the ubiquitous 'stranger in a strange land' trope - each character is entering a situation where they have some backstory to color events but is completely ignorant of the situation they are entering and 'the rules of the interpersonal game' between the two. Everything said is new to both characters, so every bit of exposition is part and parcel with the situation, and the day-to-day trivialities aren't glossed over, they were simply missing to begin with. There are many ways in which the situation is handled that augments or adds something completely independent of the premise, but the foundational premise is something that cannot be counted upon in Before Midnight. Even the vacation that the couple are on is almost over, and the only 'fresh' event is just a trigger for one line of conversation in amongst many. In that sense, there is simply so much that either must go unsaid between the two or must be said inorganically to the audience to bridge the gap in knowledge. Which is not to say that any of the latter is done, it's just a fundamental element of the premise. Before Sunset is special in that there is almost no possibility for reverse dramatic irony, which is to say that the characters can't know more than the audience. This is certainly not the case in Before Midnight. In every fight, Jesse and Celine know each other's affectations to a far greater degree than the audience. This brings into question all sorts of possibilities and eventualities which were not possible in Before Sunset, and in many ways Before Sunset bathes in this uniquely blissful naivety, and it makes it special. Before Midnight can be compared dramatically with Everyone Else, while Before Sunset can only be compared in the quality of its human insights and empathetic truth to Everyone Else. What I'm getting at, essentially, is that Before Sunset is a film about that unique phenomenon of which the experience of Before Midnight was, and Before Midnight is a film about stuff that lots of other films are about, and while this may not mean anything, it exists. Looking at my favorite films, the inherent power and uniqueness of the premise certainly acts as a boon to my enjoyment, and Before Sunset trumps Before Midnight in spades in this respect. It also trumps Before Midnight in its characters' unceasing adorableness, which groups it with that actually-pleasant variant of 'pleasant cinema' which I so love. So when I say that I do not love Before Midnight immediately as much as I still love Before Sunset, it doesn't really mean anything. And to many others, when they find that they love Before Midnight so much, and it is aided so much by it being so new and long-awaited, it doesn't really mean anything, either. What actually does mean something are those things in the film which will be meaningful to me in 9 years, when the next event hopefully comes along. And I don't really know yet. But it'll have to contend with repeated rewatches of Before Sunset, which may give it the defeat by default. Nobody ever said love was a fair fight.