"[The sorting hat] only put me in Gryffindor," said Harry in a defeated voice, "because I asked not to go in Slytherin…""Exactly," said Dumbledore, beaming once more. "Which makes you very different from Tom Riddle. It is our choices, Harry, that show what we truly are, far more than our abilities." - JK Rowling

Be a sadist. No matter how sweet and innocent your leading characters, make awful things happen to them ― in order that the reader may see what they are made of. ― Kurt Vonnegut