Doki Doki Literature Club (Lore Explanation)

Your first run of the game will be, normal. To say the least. For instance, I chose to basically "court" Yuri. In turn, this caused issues with Sayori's feelings. She started to become more distant, and, in the end, she unloaded on me saying she's been depressed all her life. While she's glad I was able to meet new friends, she's conflicted and extremely bothered inside since I haven't been doting on her too much even though we've been friends since children.

Even after giving her comfort and telling her I was her "dearest friend," she ended up hanging herself the next day... ... ...........

Which... is where the game gets weird. As soon as you get any of the "death" endings, the game freaks out a bit, and gives an error in the background of the current death scene, with a reference to a specific file in the game's directory.

Opening this file shows that the game had an issue and recompiled itself in attempts to patch around the error caused by the death scene, but... that isn't the problem. In the text file, at the end of the traceback log, it states... "This one is causing problems. It'll be okay if I just delete her."

If you somehow manage to get the correct path, which requires a bit of save/load manipulation, everyone ends up dying in the end except "Monika." When you get to her however... she stuffs you in a never-ending loop, and if you click it a specific amount of times... then delete her character file

...

You get the game's "Special Ending" Credits.

And, if you get another specific path... it turns you Monika is actually the one doing these things, killing off the characters, and deleting their character files. She is the one who wrote that "It'll be okay if I just delete her." In fact, if you start the game on that route I mentioned after Sayori dies... Monika glitches in to replace her.

TL;DR:

Basically, the game wanted you to be with Yuri if you take the Yuri path. But, when it detects Sayori wants your comfort... it goes in and kills her, because you're meant to be with Yuri. Monika is the representation of the game's will. Which is why it sometimes gives you "hints" (actual game mechanic tutorials) and says "Wait, why would I say that?"