Some good quotes that are related

All judgment is comparative.

—Samuel Johnson

What should they know of England who only England know?

— Rudyard Kipling

What should anyone know of anywhere, who only that place knows? 

— Anthony Daniels

A bug that spends its whole life on a leaf doesn’t know what a tree is.

— Unknown

I guess this means a world traveler gains knowledge not only of the places to which he travels, but also of the place in which he normally lives.