I think I might have a slight touch of insanity. Or maybe the better word is obsession. I write during the day. I consider this my job -- my hours of operation, ya know? And I love, love, love my job. The obsession comes in when I continue to write on weekends and at night on a secondary project -- like its my hobby. It should be overkill, but somehow it is not.
I have never, since I began writing seriously ump-teen years ago, written on one project at once. (And kudos to those who write this way, and have found what works best for them). I've actually tried that, and it stifles me completely. It's very constraining to my creative process. So, I'm always writing a rough draft of one thing and then polishing something else on my free time. Or revising a main project while making notes on a new project. It's like I need or thrive upon the creative fuel of multiple projects. One feeds the other in amazingly positive ways.
Just my morning observation... turning in Le Super Secret YA project to my agent last night made me think of the way I write, the way it works best for me, and ideally what kind of career I want to have, and what kind of writer I am most comfortable being.
And fingers crossed for the YA, folks!