Bravery is associated with Gryffindor, and Peter Pettigrew was a coward who betrayed all of his best friends. My parents" blood is on his hands. Professor Quirrell was a Ravenclaw who allowed Voldemort to live off of him as a parasite. Good and evil do not equate to what traits you value, it is equated to how you decide to use them, whether it be for the benefit or harm of others.