it would be unsafe to drive cars, especially in the night. You will only get a smaller field of view and also, there would be no spherical mirrors in street lights to spread it. Also, there would be no solar furnaces, leading to increased use of fossil fuels, which will destroy the environment. Dentists cannot properly analyse the problem in your teeth that are in the back of your mouth. Many large telescopes to observe the universe will not be present. Combination of spherical mirrors are used in many printers and physics experiments.