Some things are governed by common sense. Putting buttons on the front of a shirt is a matter of logic, since it would be very difficult to button them up at the side, and impossible if they were at the back.
“Other things, however, become fixed because more and more people believe that’s the way they should be. I’ll give you two examples. Have you ever wondered why the keys on a typewriter are arranged in that particular order?

Autor: Paulo Coelho