It's the line that made me
Well golly...I don't think anybody said that until Dylar posted it.
Folks that want to understand more about the facts of fly lines and casting will find the linked article by Bruce Richard to be informative and beneficial.
Learning and understanding the few basic principles of casting and correctly applying them... will make you a better caster. Fly lines vary in their design, head length, tapers etc. Learning about these differences and how they can impact things like roll casting, mending and aerializing longer lengths of line can help you understand what works and what doesn't and that will enhance your casting ability. Some fly lines do a lot of things pretty well. Some excel at certain tasks...other designs won't perform those same tasks as well. And in many cases the average caster, and sometimes even the beginning caster, can realize the difference.
Not everyone wants to dig that deep into the facts of casting and line design and that is fine. Those folks will be well served with standard weight forward or double taper lines, when those lines are cast with good fundamentals. In fact, they may even be very surprised at what lines and rods are capable of.