The Stamp Collecting quest in NieR:Automata which takes place at the Amusement Park, how it relates to 9S psyche and diving into 9S as a character. (Thread with Spoilers)

A amusement park is always remembered as a happy place, lots of positive emotion and many other emotions as well. A person who is exactly like this is 9S in the beginning of the story, being very curious and naivete ever since he was created.

The amusement park is very different than we see it in Route C rather than the first two other routes which are A and B. The positive energy of the happy machines have turned into "zombies" after Adam and Eve have been defeated from the world. 9S mental state started to decline

at this point after 2B's death. 9S very happy personality is now filled with hatred and despair. The only thing that left was with 9S after that was the desire to eradicate all machines and A2 and then himself especially knowing everything that was told to him was a lie.

"Did you enjoy your time here? Or maybe not? Well, it doesn't really matter. Though I'm sure you realize that by now. Whether or not you enjoy something simply depends on your own heart. This place is but a mirror that reflects one's true self back at them.”

That quote can also represent other things as well such as how it's a imagery of happiness but overtime eventually you see the more depressing aspects of it. This game is honestly on how you make of it, it's up to us as the players to see how we interpret the story.

9S has to be one of the most interesting characters ever and one of my favorites. He at first was struggling with the idea of killing machines but through more hacking, he uncovers more stories behind the machines and by the end of Path B, 9S reaches a point of cognitive

dissonance where he sees the machines more than what he originally thought them to be, also he develops affection for 2B which adds more confusion to his programming and emotions are prohibited for them.

9S is one of the best written tragic characters, after seeing 2B's death, he was unable to cope with that and just lashing out at the world. I know a lot of people don't like 9S knowing all this especially after Route C but thats a sign of a amazing well written character.

Thank you if you have read this whole thread,
NieR:Automata is one of my favorite games and 9S is one of my favorite characters. (End of Thread)

Thank you @yokotaro for NieR:Automata.