a world without pain?

Just imagine a world without pain. When a nail penetrate your foot, you would't realise it cuz you cannot feel the pain. Then, you'll get into big trouble by losing a lot of blood and die eventually if u cannot fell the pain from it. I once read a storybook about people that cannot feel pain. Their ancestors were brilliant scientists. They managed to remove the pain reseptors from their genes. As a result, human cannot feel pain. Many babies became deformed cuz they didn't know the danger of sharp things or by rubbing their eyes too hard till they grew blind. Many are without legs and hands. They can only learn about the danger of the world from school or from their parents. Many of them vowed to return their sensation of pain back to their body. Another book Brisingr by Paolini describe about a army that cannot feel pain. Imagine that... They will fight till their last breath.