Why is it important to use systems analysis and design methodologies when building a system?

Why is it important to use systems  analysis and design methodologies when building a system?
Why not just build the system in whatever way seems to be “quick and easy”?
 What value is provided by  using an “engineering” approach?
Also, Give a specific example of an  organization (not one listed in the book) that does a good job of this and why.