Quentin hummed a response instead of giving a verbal one, although he wasn't convinced. But nor did he think he was going to convince Snape that socialization was a good thing. Certainly not in one brief conversation. Probably not ever. He was many things, and yes, arrogant was one of them - but stupid was not.
"Oh I have no desire to be a surrogate father - or mother - to anyone," he said with a chuckle. "Fortunately I've some decent prefects." And they could play the parents if they wanted to.