We often form stylized images of the world around us and when we find something that does not conform to our internal image, we conveniently forget it exists. If I asked fifty people to draw a cactus, I would likely get a huge majority of saguaros. It is very unlikely anyone would draw this cactus. Why is that the case? Even those people who have never seen a cactus in their life have formed a concept of cactus that is equal to saguaro and nothing else. I think this is sad.