Let's discuss why!
Attack on Titan Season 3 spoilers ahead!
What makes Attack on Titan such a great series? Great mystery about the origin of titans and humanity's fight for existence, personal drama of characters, deep philosophical issues and, of course, breathtaking action. Attack on Titan Season 3 Part 2 has got your covered: it's got all of these elements that make the series so dear to us. To understand why this part of Season 3 is so important, let's quickly remember why we love the previous seasons so much.
The first season of the anime establishes the conflicts that the main characters will have to deal with. The story is filled with mystery, there are dozens of questions about the titans and titan shifters, their root and motives, and the viewers are given the promise of getting the answers to these questions in the mysterious basement of the Yeagers' house.
The main focus of Season 2 is on the characters. The pacing has seemingly decreased to aim attention at relationships and give more personality to those who hardly had any screen time in the first season.
The beauty of this season is that we get a lot of answers about the lore, but some of them are so intricate that it's impossible to fully understand the picture without advancing further into the story.
The first part of Season 3 forces our characters to make important decisions and keeps giving us small hints at the truth and glimpses of what has led to the current events.
Now we're finally at the second part of the season, and what can we see? That's right, all of the above! This sequence takes everything appealing that Attack on Titan has ever been able to offer and combines it. The season finale feels like a payoff after everything we've been through.
Everything that the series has been building up to is finally revealed. The characters get to the basement and discover the truth about the titans and their creation. The relationships and bonds are given enough focus and proper attention. The characters are met with existential dilemmas and painful choices. It's enough to remember episode 18 where Levi has to decide whether Erwin or Armin should survive, which is one of the most intense and depressing Attack on Titan episodes till this day.
Side characters don't feel unimportant due to the careful attention they're given. All the drama and the trauma that's led them to where they are now are explained. Although we might despise them, we can't help but understand Reiner and Bertholdt.
And last but not least, action! Part 2 is packed with astonishing and exciting battle scenes, it's difficult to take your eyes off the screen. You feel puzzled every time an episode ends because no way 20+ minutes have already passed! The only choice is to just press the "next episode" button and find out what happens next.