Dagnamit. I was just about to go there. How could this post go so long????
Since Asimov was quoted in the first paragraph, I might put fourth the example of Solaria.
/Naked Earth. OK, so it is a dead end, but it's a slow death.
fatalfury writes "Researchers from the University of Vienna asked 20 males and 20 females to rank vehicles based on their appearance. The list of traits included arrogant, afraid, agreeable, disgusted, extroverted, sad, and others. Cars with 'meaner' traits (such as BMW) ranked higher, whereas cars with 'nicer' traits (such as Toyota's Prius) ranked lower. With billions spent on developing new products in the automobile industry, this could spur a trend in meaner-looking cars and perhaps explain why sales of the Prius and other green cars are slow to take off with average consumers."
At the point society started protecting those who should be at a natural disadvantage, evolution stopped. Eyeglasses were an early contributor, but certainly not the first. Why should we let hemophiliacs breed? To breed more hemophiliacs? If a man is laying face down in the street, apparently the street has beaten him. By preserving these people and allowing them to breed, we have effectively short-circuited survival of the fittest.