Why does that mean she can't be my favorite? I think it's self evident that she's the best character, she's definitely better than the stalker office lady or his college classmates who don't have much real connection with Masato besides liking him. Yuka and Masato actually have shared interests.
true, but i think the problem lies in her romantic affection towards the mc, with her being a middle schooler and him a full grown adult
she can be your favourite character all you want, what i have a problem with is shipping these two
as long as you don't ship them, i personally think it's fine, i can't do anything even if you do ship them though
this is just my own opinion and you're free to do as you wish