Despite the best efforts of the Flat-Earth Society, the world is, in fact, a globe. However, this creates a problem since it is impossible to accurately render the surface of a three-dimensional globe onto a flat surface. Ever try to peel an orange in one piece, then stretch out the peel to a rectangle? Now you see the problem. The way around it is by using "projections" to approximate the world as we know it.
Mercator vs Gall-Peters Projectionclip from the sitcom West Wing S2 E16 Cartographers for Social Equality
VOX: Why all world maps are wrong
Atlas Obscura: North America in Pencil Crayon