“I have a role to play, the same as you, Mr Defiant Gryffindor,” Snape answers smoothly, the corner of his mouth lifting in bitter amusement.

“But you make Neville cry every class, and you scare me, and you give points to the Slytherins for almost nothing and take points for silly things like breathing too loud or asking questions!  It’s not fair.”

Instinctively, he knows that things are not fair, but he had hoped that they might be different here at Hogwarts.

"Mr Potter, one of the things you learn in life is that everything is not fair, or right, or just,” Snape says, sounding tired.

“I know that!”  Angrily, he scrubs a hand under his glasses at the strange appearance of tears.

Snape observes him for a moment before speaking again.

“My Slytherins receive punishment in private.  I do not discipline them in class for appearance’s sake.  They understand that if I award them points for,” He pauses and smiles in a frightening way, “Silly things, then they are likely to be forced to explain themselves to me once we are alone again.”

He blinks as he suddenly understands why the Slytherins never react to receiving points with anything other than silence or frowns.

Except for Malfoy, but he's a prat, so that makes sense.

“If you care so much for your Slytherins, then why do you bother to help the kids in other houses?”