The "classmates are jealous mc is close with a girl" trope is so weird. Like, my dudes, they're not even dating and just friends being friendly, what are you jealous about? Are these guys really that bad with girls they can't even befriend them?
They didn't exactly know each other back then right?
But yeah, it's definitely a romcom manga thing. I'm sure it's not that big of a deal in real life.
I still can't get over the fact that Kusunoki calls MC with his first name.
From all the romcoms I've read, I learned that unless they're childhood/old friends, calling first name of someone opposite gender is supposed to show a very close relationship and probably more than just friends.