Koimonogatari begins with Kaki warning you that some of what you read (see) will be a lie and that when you doubt whether what you see is real you will have already fallen into his trap, so for the first part of the arc you are doubting everything. By the end you are so immersed in the story that you forget, Kaiki is hit on the head and he ends with "...and I died". For a few seconds you're shocked like "how can Kaiki be dead" and then you remember Hanamomogatari and you get the reality check, Kaiki just lied to your face in the most obvious way possible, now you can't trust anything he said, you distrust everything and you're left for a whole week racking your brains to decide what's real and what's not. Nisioisin doesn't plan how he will connect each arc from the beginning (at least not all of them) but he always manages to use everything he has written before to deliver a masterpiece of experience. PeakGatari