Gryffindor: when they lost a quidditch game

Ravenclaw: when they forgot the bonus task in a test

Hufflepuff: when they're alone in their room and they want to prove themselves that they're rebellious and wild because someone called them "a boring nice girl/boy" previously

Slytherin: when-fucking-ever it's on their goddamn mind, dumbass. why the fuck did u ask