17. People can surprise you:

The old saying ‘never judge a book by its cover has been trotted out hundreds of times and yet all too often we don’t really appreciate its meaning. Making a snap judgment about someone is a risky business, as these books have shown us. A towering half-giant could turn out to be a loyal, kind, and gentle friend while a stuttering, nervous teacher may be harboring Voldemort in his turban. A dark, bitter Potions master may sacrifice everything to right a wrong for the love of his life, and even a paragon of wisdom like Dumbledore could have a complicated past. People aren’t always what they seem