I forget the name of the guy, but there was a Belgian Grand Prix driver in the 1920's who was at a party with some friends. He decided to go into some bushes and pretend he was a wild pig to frighten his friends. Duly frightened by the noise and rustling in the bushes one of the party took out a gun and shot into the said area, killing the guy stone dead.
There are millions of people in the world. And none of those people is an extra. They're all leads in their own stories.
If you lose one sense, your other senses are enhanced. That's why people with no sense of humour have an increased sense of self-importance.