I randomly skipped over this but 28 pages of comments kinda made wanna check it out and... it's okay I guess :P
Anyway, since Risa is apparently a hot topic :P I can't help but think there's some weird discrepancy here - in Risa's flashback, they're both presented as kind of outsiders in their group at work and they basically bond over that... but in Ayaka/Hiroko flashback, Risa appears pretty well integrated in the team already and it's just Ayaka who's the odd one out with Hiroko helping her. ...so I dunno, either I misread these, or the author did something weird.