This 'Game of Thrones' episode was the best TV episode of 2017, because it relied on its complex characters more than spectacle

Sansa and Arya's reunion could have been awful, filled with a lot of hugging and crying.

But Sansa and Arya's relationship is complicated. Growing up with completely different personalities, they kind of resented each other, even though deep down they always loved each other. But it's been so long since they've seen each other that they don't know if they can trust each other anymore.

From Arya's perspective, Sansa let their father get executed by King Joffrey, because Sansa always wanted to be a princess. And now, with Jon Snow gone, she is the Lady of Winterfell.

From Sansa's perspective, Arya arrived in Winterfell unexpectedly and didn't hesitate to announce that she kills people now. Who's side is she on? Sansa has no idea, and neither does Arya. Their enemies are common, but they don't trust each other enough to reveal them.

The reunion in the crypts of Winterfell packs all this built-up resentment in, and adds a little joy. Despite all their differences, experiences, and loved ones lost since they parted, they're still excited to see each other alive in their home of Winterfell.

Theon Greyjoy has come a long way and been through a lot (years of captivity and psychological torture at the hands of Ramsay Bolton) since he took Winterfell and pretended to kill Bran and Rickon back in season two.

But Jon Snow doesn't know this. All he knows is that he saved Sansa, which Jon says is the only reason why he doesn't kill Theon when he and the surviving Greyjoys come to Dragonstone.

There's also a lot Theon doesn't know about Jon, like that he literally died.

Littlefinger, though awful and creepy, is one of the best characters on "Game of Thrones." Aiden Gillen gives one of the best and most underrated performances on the show.

Bran and Littlefinger, the two creepiest creeps in "Game of Thrones" history by a long-shot, have a scene together. It is creepy. Littlefinger gives Bran the dagger that was used back in season one in an attempt to murder him.

Littlefinger gives this to Bran in order to develop some some kind of understanding: Littlefinger knows that Bran has special abilities, so he can probably see what Littlefinger's done to the Starks in the past (he murdered Jon Arryn, betrayed Ned Stark, murdered Lysa Arryn, for starters).

But Littlefinger's games don't work on Bran. Bran keeps a creepy straight face in this scene and throughout the rest of the season, which makes his role in helping Sansa and Arya betray Littlefinger in the season finale very powerful.

For the battle, McLachlan told Business Insider that they wanted the smoke from Drogon's fire to be black, so they burned diesel.

"After a few days the cast and crew were hacking," McLachlan said. "Our faces were black, even though we were wearing masks. And the actors couldn't wear masks, since they had to be on camera. The HBO health and safety officer told us we had to stop using the diesel."

McLachlan also told Business Insider that shooting the Loot Train Attack was "a really daunting action sequence."

"This battle is massive, so it was important to keep the momentum," McLachlan said. "We were also under a lot of pressure, since the 'Battle of the Bastards' was one of the best battles ever filmed, including television and movies."

A battle with hundreds of stuntmen, horses, and fire would be hard to shoot as-is. But on top of that, there's also a dragon flying over the field.

The Loot Train Attack showed Daenerys riding Drogon for a longer, more involved period of time than we've ever seen before while she roasts Lannisters like they're hot dogs at a very violent Fourth of July barbecue.

In August, Business Insider talked to the "Father of Dragons," Sven Martin, about what work went into shooting Daenerys riding Drogon in "The Spoils of War." Martin is the visual effects supervisor at Pixomondo Studios, where he has been working on the dragons since season two of "Game of Thrones."

"Having Dany interact with the dragons is the most complicated thing to create, because you have a lot of preparation time, but it's a very technical set with this flight simulator and the performance," Martin said. "And then after shooting, you have the lighting and connecting the performance with the dragons."

We've seen Dothraki fight before, but never in a battle like this.

But through all the seasons, we've heard characters mention the Dothraki's battle skills, though no one expected them to actually conquer their fear of the ocean and land in Westeros to fight for Daenerys Targaryen.

Seeing the Dothraki in action proves how powerful Daenerys is compared to Cersei. The Westerosi aren't trained or prepared to fight them, and from what we see in "The Spoils of War," it looks like even when expected a fight, soldiers in Westeros aren't good enough to keep the Dothraki at bay.

By alternating between multiple perspectives during the loot train battle, "The Spoils of War" makes people question their morals and loyalty to certain characters.

Unlike other battles on the show, "The Spoils of War" shows how innocent people who just happen to be soldiers for the Lannister army are affected by the main characters' selfish obsession with gaining power.

Cersei Lannister, at times, is a sympathetic character. But she has always been a villain, and in season seven she's a full-fledged monster and pretty much murders all the time. During the Loot Train Attack, her army is so devastated that it's hard not to feel bad for them, and at a certain point, root for them.

Leading her army is Jaime Lannister, who started out as a villain in the first two seasons, but after his season three journey with Brienne and losing a hand, he's a changed man. His perspective in the battle helps the audience question Daenerys' decision to surprise the army with this brutal attack. The only thing that hasn't changed at this point in the season is Jaime's loyalty to Cersei, who he seriously questions after fighting Drogon and the Dothraki.

In Bronn's perspective of the battle, which is probably the most anxiety inducing, we see a man who is just doing his job. Bronn doesn't care who wins the game of thrones. He is just trying to make a living, but he has to fight a giant fire-breathing dragon to do it, because the people who pay him are fighting the woman riding it.

And then there's Daenerys.

Despite Tyrion's advice not to surprise the Lannister army with this attack, Daenerys goes for it. She's mad that she's losing the game of thrones, and she doesn't feel like waiting for Tyrion's grand plans to play out.

Daenerys seems to enjoy herself during the battle (the Mad King was obsessed with fire), and doesn't hesitate to bring devastation to an entire army, which is mostly innocent soldiers who happen to be from the Westerlands.

This battle, and the following episode where she punishes the men who fought for the Lannisters and refuse to be loyal to her (the person who just slaughtered their people), might hint that Daenerys has a dark future ahead of her, reminiscent of her Mad King father and the many Targaryens before him. That would be a sad end to the series, but would be an effective surprise that this series is known for pulling off out of nowhere.