Woohoo

Quite late in the series, pretty much near the end, it is revealed that since Eren has the Attack Titan, he is essentially an omnipotent god who knows the future and, this is real, he went back in time metaphysically and actively made that particular titan eat his mom. Eren killed his own mom. Why? To apparently motivate his past self to...do what has already happened...yeah. On top of that, Eren becomes a big bad guy because of course, and vows to wipe out all of humanity to protect Paradis. He begins that process and for no reason whatsoever, stops at 80%. Unless we count the terrible reason he gave, which was something like "I want you guys to look great when you kill me so nobody will mess with you!", even though Eren ends up breaking down and crying, and also saying that he loves Mikasa and that nobody else should have her, even though they've NEVER loved each other like that. 

Oh and Marley? The place that was essentially nazi Germany and vowed to wipe out Paradis? Armin decides to team up with them to stop Eren, because oh noes he is the bigger threat, even though Marley was hellbent on killing Paradis, which is why Eren started the whole thing, I guess. So Armin teams up with the nazies, and they defeat Eren. Eren dies, and the titans come to an end, supposedly, and so does the war. All is wonderful. Except, right at the very end, 150 years later, Marley attacks and wipes out Paradis anyways, meaning that the entire story was for literally nothing. Also, remember, Eren knew the future because he kissed the hand of royalty, so...he knew he would "lose" I guess, so why did he go back in time to murder his own mother to motivate his past self to fight for a future that he already knows is doomed? He knows he is going to die, and he knows Paradis gets destroyed anyways. 

All of that is without even mentioning the other stupid bullshit, like the pocket dimension, the original titan girl, and that Eren's head, when buried, results in the tree that caused the Titan curse to be grown again, meaning titans will come back. I am not kidding.

This, to me, is by the most egregious form of story self-assassination I have ever witnessed, and I doubt anything will ever top it. It literally makes the entire story mean nothing. It retroactively destroys the entire story, even as far back as the very first episode. Every single thing in this story didn't matter, because the very end ruins every ounce. It is infuriating. It feels like the writer wanted to avoid a "traditional" ending, and decided to act like he was being all sorts of "philosophical" and "deep", when all he did was kill the very thing he had been building up for over a decade. I would have absolutely taken a traditional good vs evil story and ending over this, any day. Not to mention that he stretched out the final parts and the final season for years, just to milk it for all it was worth before he nuked it with the ending. I had so much passion for the series, and all of that passion, like the story itself, was all for nothing.