There hasn’t been a single web series (or movies too) that didn’t try to mimic reality as best as it can in its most rudimentary form. Attack on Titan does the BEST mimicking Reality.
However, Attack on Titan anime takes this notion of portraying reality a step further by not only mimicking reality in the best possible way; but also encapsulating it in such a way that even a teenager could grasp it effortlessly.

*Spoilers ahead, so, read at your own risk*
Think about it for a moment, and answer the below question.
What is the most fundamental fabric of reality that we humans are tied to?
That’s right. Pain, suffering, and mere catastrophes.
Don’t get me wrong, not saying that all these things are particularly ‘Bad’ (whatever that means to you in your own sense). Or that life is nothing but a long lifetime struggle. (which is totally the case by the way)
Did you just see what I did there? In the above paragraph, I tried to avoid the very same things that I said were building blocks of human existence. Did you know why I tried to avoid the very same things that I know are inseparable parts of our lives?
It’s simply because we humans hate the idea of pain and suffering. The very idea of it causes agitation. But; what would happen if that were not the case? How would you react? Will you be tormented by the very idea of death every moment of your life? Or will you start living your life more open to challenges?
That’s the neat part, each one of us will react to the situation in an extremely different way, right? Definitely, there will be a hell lot of stress and struggle involved in trying to cope with the fact that you are 24/7 in the hands of Death. That is what Attack on Titan depicts the BEST.
The basic idea is ─ you are encircled by human-eating monsters (also called Titans) at all times. The only thing separating you from those monsters is a wall. A wall that is also made up of monsters. So, not only you are separated by death (all thanks to the door) but also the same door is death if you crack it open.

Then, how does it feel to be held captive by these flesh-devouring monsters?
NOTHING.
YES, YOU HEARD ME RIGHT. ABSOLUTELY N O T H I N G.
Why? You might ask. The answer is pretty simple people enclosed and held captive in the walls aren’t even aware of the fact that there is a world beyond those walls. So, they are pretty grateful for the fact that as a society they are able to flourish within those walls.
Walls have three layers in a form of circles protecting the kingdom situated in the core. People living in those Maria, Rose, and Sina. Starting from

However, you might say that although they might not be aware of the world beyond the walls they sure are aware of the fact that these monsters could anytime break the walls and they, themselves, might become breakfast, lunch, or dinner of those monsters at any moment in time.
Indeed, I’d be lying to you if I said that they were totally ignorant about the exact same possibility. They weren’t. They were cognizant of this scenario. However, the case might have been that the people living in those walls did not forget about this possibility but they thought that this scenario was highly unlikely; because these walls didn’t have a scratch on them for the past two centuries. Until one day…

UNTIL ONE DAY… AN ARMORED TITAN BREAKS THOSE WALLS
Until one day… a Titan bigger than the walls breaks the outermost district part of wall Maria. And then, you know, Titan eats the protagonist’s (Eren’s) mother (Carla) and then Eren furiously decides that he is gonna Kill each and every last one of those monsters. But he fails miserably, yada yada yada…
It’s all a good story arc for the main character until we find out that Eren himself is a Titan. Wo-ho, he became the very thing he hated the most.
The best redemption story structure is laid out perfectly. That’s what happens when a plot twist has a plot twist of its own. That’s how reality functions. The only thing you do know is the things you most care about; but, then, you get to know the things that you didn’t know before and you also didn’t know that have to know them in the first place.
However, now that you ‘DO’ know those things, LIFE becomes a bit more complicated and gets tangled in a mess.
What you also start to observe during this anime is that not only do you know what are they talking about and how are they feeling but also that you are also able to feel what they are actually feeling.
HOPE: Attack on Titan
All the terror, remorse, panic, and amongst all negativity they still choose not to abandon the hope. Hope that they would be free one day. Free from the cage they had put themselves into.
It’s all like real life, you get up from your bed every morning (or at least most of the mornings.) Then, you get up and get ready for work. Even though you know perfectly well that this very well may be the last day for the rest of your life. But you still choose to look on the brighter side, towards hope.
Hope is the force that drives all of us. You, me, and every individual out there have nothing but mere hope. And that hope is enough to sustain oneself from all the negativity all around us.
You see this everywhere, in every Marvel or DC comic. There is a protagonist. A symbol of hope. Our ideal self. The one hero that we aspire to be the most. A villain that we hate until we get to know his/her backstory. Once we know the villain’s backstory, then we are able to sympathize with them. This has always been the case up until Attack on Titan.
So, what is it that separates attack on titan?
Attack on Titan is a twisted-turned story of a person, who lost his mother to a flesh-devouring monster and at last, he became the very same thing he used to despise.
All Eren does now is… ideate phobia in the minds of others for the Freedom of his friends and families. Deep down he knows that if he continued to move forward he would gain nothing but his friends and families could prosper. He is fighting not only for the freedom of his friends but also for the freedom of his younger self which had been snatched from him and his loved ones, a very long time ago.
How long ago you asked? Oh, long-long time ago. About 2000 Years ago. I am glad that you asked.
Think it critically, would you like to suffer the consequences of a crime you never committed?
No? Right? But, what if you had no other choice? That’s the final story arc of Attack on Titan. There were no protagonists or antagonists in the first place. However, there surely were experiences. Experiences of all the people who suffered throughout the character development who didn’t even commit a crime in the first place.