Harry Potter and the Sorcerer's Stone
"I think I can tell who the wrong sort are for myself, thanks," he said coolly.
Draco Malfoy didn't go red, but a pink tinge appeared in his pale cheeks.
"I'd be careful if I were you, Potter," he said slowly. "Unless you're a bit politer you'll go the same way as your parents. They didn't know what was good for them, either. You hang around with riffraff like the Weasleys and that Hagrid, and it'll rub off on you." (6.246-248)
You might belong in Hufflepuff,
Where they are just and loyal,
Those patient Hufflepuffs are true
And unafraid of toil… (7.33)
Don't you care about Gryffindor, do you only care about yourselves, I don't want Slytherin to win the house cup, and you'll lose all the points I got from Professor McGonagall for knowing about Switching Spells. (9.132)