The movies will do that to you. I keep thinking of the first movie where Harry first plays against Slytherin. The seeker (pre-Malfoy) looks just like I pictured Cedric Diggory would look. So in my mind's eye I see Cedric Diggory wearing Slytherin colors even though I know he belonged to Hufflepuff. I should go soak my head in some Erase Juice.