If you have something to work with, it makes it 1,000x easier to edit, iterate, and improve on what you've got. That's just another reason why I like to put my immediate thoughts together whenever I'm handed an assignment or something where I have to use my creative abilities. This for me means that I can still rely on instinct; jumping into things without giving too much analytical thought, then mulling it over before really getting into the nitty gritty of it and editing, iterating, and improving.

It's true that everything starts with a simple idea, but a simple idea with a little bit of back work, or as I like to call it writing up your intuition, can go a long way.