I had to stop reading halfway through because I finally realized.
She has a facial muscle/nerve dysfunction/paralysis. And yes, I heard couple stories of people getting bullied for not being able to show any emotion on their face even if they laugh.
@Randomizer She is not getting bullied, though. Everyone else is okay with her and the one guy focused on her lack of expresions does it out of a childish sense of competition, plus he is the guy she likes so obviously she is more than happy to get his attention.
@Randomizer Well, she likes the attention actually, everyone else just stayed away from her, the MC is the only one who always stays by her which is why she likes him.
@Acolytus@Darklight99
This guy does not understand what she feels, and that provokes him to bully her, even though he is attracted to her.
Oh well, this is manga anyway. Let's not take it seriously.
Please enlighten me, I have never seen anyone grinning looking at a porn site, I only ever see them with expressions full of desire. Is the norm as mentioned in the manga or in my anecdote?