As a writer, it is an important skill. You need to focus to get all the great imaginative stuff jumping about in your brain into print mode (be it paper, computers, whatever) and it is often so damn tough because you get distracted by the idiocy of the world. It is easy for writers to get lazy too-I have been working on 2 books and editing Tree of Bones for my second "Familiar's Tale" book. But my focus has been dreadful. I keep getting distracted by trivial things, the way Mellypip gets distracted by a drobba-chip cookie. I have much of book 3, Fires of Rapiveshta, running scenes in my head. As I try to write it I keep getting scrambled by which part of book to write. It is very annoying because I have the last half of the book worked out but the first half is still taunting me.
I have resolved to be made of tougher metal-because when I am focused and writing-I feel better. My mood is less glum. I am less cranky. I even stay on my diet better (though drobba is always a danger)
Focus is what makes for success too. In all things in life-if you have your goals and energies directed where they should be-into your art-you will eventually succeed.
Now, I must get back to writing Fires of Rapiveshta and my 'other new fantasy' novel (The Legend of Rose Greenleaf, The Dwarven Bardess of Rhulon- a working title only).