There are as many rankings of MCU films as there are MCU fans. Each one is unique, but most of them are relatively similar; with the Winter Soldiers and Black Panthers near the top, and the Thor 2s near the bottom. As an MCU fan myself, I of course have my own personal list, and the big idiosyncrasy of mine is that I place Guardians of the Galaxy at number one.

By the time Guardians came out, in 2014, it was the tenth MCU movie and the Marvel house-style was well-established. The movie does not represent a dramatic break from that style, but as I watched it for the first time in the theater, it was different enough–surprisingly funny and refreshingly weird.

The movie also has a terrific cast. Chris Pratt is perfect as the (aspiring) rogue Star-Lord. Dave Bautista was a revelation as Drax and Bradley Cooper is a riot as the voice of Rocket. No one alive looks better painted different colors or beating the crap out of people than Zoe Saldana (though Karen Gillan comes a close second).

The focus for this article, though, is Vin Diesel, who voices the tree-man Groot. Diesel is usually the butt of a lot of jokes for his limited range, and rightly so. However, he does a fantastic job in this film. He manages to find and convey every possible emotional intonation of a single, three-word phrase, “I am Groot.” That is no easy feat.

For the vast majority of the film, this limited vocabulary is played as a joke. Not only is the tree’s response to everything “I am Groot,” but, amusingly, some characters can actually understand him as if that phrase means something. And to be fair, again, Diesel manages to put every spin on that phrase conceivable, keeping it from getting boring. (I can hardly imagine what a day in the recording booth must have been like for the poor man.)

The payoff for this running gag comes at the end of the movie, and it goes, unsurprisingly, but still effectively, to an emotional place.

There’s a phrase I often turn to in situations like this, which is “The story writes itself.” There are rhythms and patterns in story writing that give you a feel for what beats are coming. Does this make certain stories predictable? Sometimes. Does it make them bad? I would argue no. Everything comes down to the execution- how well executed is the payoff?

I have seen it argued that unpredictability in storytelling is, in and of itself, an unambiguous good. Zigging instead of zagging, pushing the story in the opposite direction that the audience feels it ought to go, this is what a story should do. I disagree with this thesis. Surprising an audience can be good, but not when it comes at the expense of the story. Sometimes, a story wants to be told a certain way. It has been set up such that it needs to continue and pay off in a certain manner. To upend that simply for the sake of surprising the audience warps the story, and for minimal gain.

I plan to write more on this idea another time but suffice to say, for now, I do not subscribe to the theory that “predictable equals bad,” anymore than “unpredictable equals good.” (And indeed, oftentimes the “unpredictable” move is less surprising than an author thinks it is since it frequently just represents the opposite of the expected play, rather than a truly innovative lateral idea.) For this article, it is enough to say that people feel the rhythm of a story, and they like to feel the beat go on.

When I say “the story writes itself” in Guardians of the Galaxy, what am I referring to? From the moment one hears a character say “I am Groot,” and learns that it is the only thing he can say, the mind goes to the natural variation on the phrase that we might expect the character to use. Especially when you’re watching a movie about loners learning to trust each other and form a team-cum-ersatz family.

At the end of Guardians, things are looking grim. The team is on a crashing ship, and there’s no hope of getting off in time. Groot, who up to this point has been a relatively minor character, mostly used for comic relief, chooses this moment to step up, and sacrifice himself to save the lives of the others, growing himself into a protective sphere that will soak up the damage and keep his new friends safe.

When Rocket, his closest friend throughout the movie, asks him why he is doing this, he gives his answer. We all know exactly what he’s going to say. The story demands it. There’s nothing else he possibly can say. Despite that–and equally, because of that–the moment lands, and to this day it brings a tear to my eye. We are Groot.” You don’t have to speak Tree to understand exactly what he means.

Once again, full credit to Vin Diesel for delivering this simple line with all the gravitas he could squeeze out of it. (His experience on The Iron Giant probably helped him with this role.) The way he gives extra, rumbling emphasis to the “we” is what truly makes the line work.

There are a couple of nice directing touches by James Gunn (who also wrote the screenplay, together with Nicole Perlman), as well. As the smoke clears, and we witness the carnage wrought by the crashing of the ship, “O-o-h Child” by Fire Stairsteps plays. In a movie filled with great needle drops, this one is particularly inspired. The sentimental tone of the song fits perfectly with the act of self-sacrifice we’ve just witnessed and leads us into the sound of Rocket’s anguished cries fading in as the score recedes.

Equally nice is a moment just a few scenes before the big sacrifice. Upon entering a darkened corner of the ship, Groot releases hundreds of glowing, floating seeds into the air, lighting up the darkness.

This is a lovely touch, for several reasons. First, it is a nice moment for Groot’s character. It reveals a previously unknown ability that he has, and it is truly wondrous. The fact is that the light comes from inside of him; it’s almost as if his own internal goodness is bringing light into the world.

Second, I like this moment because it creates a pause in the action, for no greater purpose than to simply create something lovely. Not every action movie would do something like this, and its small touches like this one that makes me appreciate Guardians of the Galaxy as a cut above more standard, cookie-cutter fare.

Guardians of the Galaxy is my favorite MCU film for several reasons. It’s very funny. It has a stellar cast with excellent chemistry. Most of all, though, it has surprising amounts of heart. The movie isn’t groundbreaking in the way it delivers it to you–anyone who didn’t realize Peter’s gift was “Awesome Mix Volume 2” in the first scene wasn’t paying attention–but it executes well, and is still satisfying. That is enough.

Once a story starts, the end is often written in the beginning. Just because you see it coming, doesn’t mean it can’t still bring a tear to your eye.

After all, we are Groot.