Fly-casting plays a very important part in fly-fishing. For some it might be just a mechanical process. For me, fly-casting is an art form, the art of casting the fly line in order to present the fly in a perfect manner, with precision and grace.
Fly-fishing is different from all other styles of fishing. Fly-casting is the answer why and it is maybe the most challenging aspect of it.
I put a tremendeous amount of time and practice in my casting and sometimes I feel that I barely started. This is a process we can start learning and one that we might never completely understand.
To quote a great fly-casting instructor: "Fly-casting is a school for life that we will never graduate.", Christopher Rownes, http://www.christopherrownes.com.