Sweet Nectar of a Poisonous Flower

Oh boy, it’s a glasses girl!

Reality: "Omae Wa Mo Shindeiru."
Yanami's Illusions of Nakatani being a plain, simple girl: "Nani?"

The moment he mentioned that she looked 'plain' and that there was a drinking party 'with big shots'...
Well, it was pretty obvious how things would go. She would turn out to be a bit of a slut/whore despite looking plain and innocent(?) and there would be group sex.
Also, 'Don't tell me this is the reason they're at the top of performance charts'? Clearly out protagonist knows not of the motivator known as sex, guaranteed to raise grades, help with studies, and in work, raises performance etc.
That ending though...You can't judge a book by it's cover, sure, but then again, maybe you could say he is rather ignorant...of Hentai.