This is my first time reading this, so perhaps I may be in for a surprise down the line, but Mayami's character is starting to get stale and/or irritating.
She gets a pass while other annoyances are rightfully mocked, as if it were supposed to be endearing... though it really isn't, IMO. There's also her keen insight: I know this is comedy and all, but gags and more serious matters are clearly different in presentation; she really couldn't have deduced Hijiri's budding infatuation with Shiratori from this alone, and at any rate not with such confidence.
In a manga like this where everyone has their own “weakness(es)” she ends up standing out. Here's hoping her implied romantic interest here will have he character develop in more interesting ways.