"Am I supposed to pretend muggle-borns are in the same league as purebloods? Don't be foolish, Black. If you're that intent on being an idiot then that's your issue but it's clear who holds more power and it certainly isn't muggles and their offspring." Even if they happened to be magical. Severus had tried to avoid the topic but seen as things didn't get better when he asked not to talk about it, when he offered to apologise - to Sirius, not the mudblood - and then he tried to make amends. It always got worse. So why not intentionally make it worse? It felt more in control to do it.

"I have no pity for filth." Filth like his father. Muggles were inherently revolting. It was their nature. Pathetic, primate and entirely useless. "And you stopped being my friend long before I stopped trying. It was around the time James Potter became the only man you listen to."