Common stories are when one plus one is two, a great story (as Ken Burns puts it) is when one plus one equals three. At its heart the quote implies that it's the absurd and the implausible that can change a decent story into a brilliant one. So too is it with Tasogare Otome x Amnesia (Dusk Maiden of Amnesia) which, on paper, could have easily ended up as "My Girlfriend is a Ghost". Instead it's an impassioned love story between a dorky teenager and a ghost over half a century old.
The third episode of Dusk Maiden of Amnesia (Tasogare Otome x Amnesia) has a fascinating hook: perception.
In the context of the episode it arrives when Kirie challenges Teiichi's vision of Yuuko as a busty, alabaster skinned school-girl and instead claims she is "dripping with hatred" with filthy, cracked skin. From then on Teiichi can only see this ghoulish visage of Yuuko until he forcibly excises it from his mind. It's claimed in an earlier episode that Yuuko only exists in the form of the beholder, so if someone believes her to be a wandering spirit then that's what they'll see her as.