He listens with concern, feeling bad for Yu due to the awful day, and also silently thanking someone that he didn't have to suffer through a day like that. Yosuke would be pissed after a day like that- he has to give Yu a lot of credit to be able to keep his cool for the most part after suffering through that. Though the way he's dealing with it, instead of raging and yelling, was being a little depressed, and that was saddening enough on its own.

"No way. Everyone has their off days man, and some of those kids are little shits. You can't let yourself think like that after one bad day. You did exactly what you needed to do. That lady can deal, you know how moms are about their kids. They're totally rabid! It's not cuz of anything you did. You're a great teacher. Who helped tutor me when I was failing it big time in some of my subjects, huh?"

Maybe she should teach her kid manners!