Question

Why are map projections needed

Answer 1

so we dont get lost would be a good example of a reason why

Answer 2

The Earth is a 3d sphere, but maps are usually drawn on 2d flat paper. We use different types of projections to make up for this. All of these projections skew the map in some way. Here's some examples ~ http://en.wikipedia.org/wiki/List_of_map_projections