"The main thing I've learned over the years is that the MacGuffin is nothing." Alfred Hitchcock
As anyone who has ever studied film narratives knows, a MacGuffin is an object that sets a film's plot in motion. It has taken the shape of a microfilm containing explosive top-secret information, a code that unlocks an enormous vault, a briefcase with seductively glowing contents, or anything else that a set of chracters is determined to obtain at pretty much any cost. But at the same time, as Hitchcock pointed out repeatedly, this MacGuffin is fundamentally meaningless to the movie's audience. We may be interested in how much specific characters are willing to do for it, but the actual nature of the MacGuffin hardly matters to us. As Tarantino understood so well in Pulp Fiction, that famous briefcase is much more interesting when we don't even know what's in it.
In the Marvel Cinematic Universe thus far, the Infinity Stones have been the obvious MacGuffin. Establishing the six various Infinity Stones as Sources of Ultimate Power has been the narrative glue that has (somewhat precariously) held the overall story together. As recap videos like this one insist, the most important aspect of the movies to date has been the laborious table-setting that can now be read as a decade of narrative prep work for Infinity War and Endgame, where these stones finally become truly central to the story.
But when re-watching all the MCU films as a lead-up to Endgame, the scripts' constant insistence that the Infinity Stones are hugely important is simultaneously the franchise's greatest weakness. Hitchcock's basic insight that these MacGuffin's are ulimtately "nothing" holds true in complex superhero franchises as much as it does in ancient spy thrillers. And even post-Infinity War, when non-comic book nerds are thoroughly aware of their importance to the overall narrative, it remains almost impossible to care about them even a little bit.
It's no coincidence therefore that the strongest entries in the Marvel film franchise have been the ones that mostly ignore the series' tedious world-building by constantly reminding us of the whereabouts of these Infintity Stones, and focus instead on emotional stakes that are actually worth caring about. Here's hoping in any case that the next phase of the MCU takes a page from Hitchcock's book and moves away from the franchise's reliance on MacGuffins.