We all wear masks, whether it is a mask of indifference of a mask of bravery. The point is: we all wear them.
The Gryffindors are meant to be the bravest of the lot, and they act the part, but does that mean they are all truly brave? Of course not! Most of them are as scared as the rest of us, they just act like they're not. But you can see it in their eyes. Kevin Emerson is afraid of his own shadow and he's a seventh-year Gryffindor.
The Ravenclaws are believed to be the smartest of the school, but they study twice as much as everyone else. If we all put that much time into study, then we'd all be that smart... well, Crabbe and Goyle from the year below wouldn't but they're morons. If Ravenclaws are so smart, they wouldn't have to study so much and they would be able to realize that not all Slytherins are bad. But no, they show their idiocy in that aspect. Cho Chang's friend is a total air head; I haven't bothered learning her name.
I've met Zachariah Smith. He is hardly loyal, the opposite actually. He would turn anyone in for his own benefit. People often say he should be in Slytherin, but he's not cunning enough. Not all Hufflepuffs were loyal, or if they were, they would be loyal to themselves and no one else. They wear masks like everyone else.
Slytherins! We're believed to be the 'evil' of the school, but who says we're all evil. Most of us are just angry at the world. Our parents don't love each other, they married for blood; they had children to carry on their name. There is no love in our families and they are disciplined to be polished and proper. Slytherin always has a Potions master as the Head of House because poisons are the more common way we try to kill ourselves. Slytherin has a high suicide rate. One student out of the roughly thirty-five students in each house will try to kill themselves except Slytherin. Twenty out of thirty-five in Slytherin will hurt themselves and think about killing themselves. Fifteen out of thirty-five will actually try to follow it through. I say try because Dumbledore and Snape aren't stupid, they always see it coming no matter how much we try to hide it. They pay close attention to the Slytherins, especially when we start snooping around Snape's private storage room, looking for something to kill ourselves with.
But they're not as observant as they believe. They didn't notice one Slytherin. One Slytherin that didn't go to the storage room but took the poison right out of her cauldron and slipped the vial into her pocket! They didn't notice her absence at lunch and, when they finally started wondering where she was, they never thought to look in one of the abandoned dungeons.
Like I said, everyone wears masks, but sometimes, they crack. And when they crack, some people can't handle everyone seeing who they are. I've spent six years watching four houses, noticing the differences and the similarities between them and I've worked out there's more similarities then differences. They believe they are all superior to the other but there not. They are all scared of the future, living from day to day and none will notice that one Slytherin that will be gone before dinner.
I know this, because Snape's only just opened the door to find me, and the poison has already made its way through my whole system.
He just stares at me, my mask long gone to show the Pureblood with the insufferable drunk mother. I stare at him for a moment, the Slytherin I had always admitted and watch his well built mask crumble just before I smile and welcome the blackness of death.