Imagine, though, if you were dying of thirst (you are, you’re a writer) and the person holding the hose kept shutting it off so they could adjust something. Spurt of water; shut it off, adjust. Spurt of water, shut it off, adjust.
You’d strangle ‘em, screaming “Just give me the water!”
That’s what your heart is doing when you write slowly, methodically, with your head. Because you don’t write with your head, you write with your heart. You edit with your head.
No one but you will see your unedited words, so don’t worry about whether they’re perfect.
Because if you worry that they’re perfect, nobody but you will ever see your words, period.