Dave is big. Dave is strong. Bob is little. Bob is small. Harry is kind. Alan is rough. Alan is bad. If someone is not huge then they are rough. If someone is not poor then they are nice. If someone is kind then they are wealthy. If someone is wealthy and not sad then they are quiet. If someone is rough and not huge then they are dull. If someone is little and small then they are sad. If someone is sad and not wealthy then they are bad. All nice people are smart. 
Dave is not dull.