Both of them are oblivious to how stupid they are. Marnie, who's still immature enough to view people as "ideas" (the way she did with Booth, Hannah does with the druggie/everyone). Charlie senses this, and what he's done is clean up the "idea" of him - Marnie's the type of girl to describe Charlie in fabulous…

what you're looking for is all there in the episode, its just that Dunham plants them so stealthily (Todd often makes very astute observations). Note:

this is a wonderful observation.

1. Junot Diaz's 'This is How you Lose Her' - sensitive, stunning, includes a story towards the end 'Invierno' that could be one of the best short stories I've ever read.