That quote reminds me of a favorite that I and the friends who were with me in college have cherished for many years:
"If it's right, it will be beautiful. And if it's wrong, it'll be funny."(The context: spoken by Mabel Lang, professor of Greek at Bryn Mawr in the 80s, speaking to a student whom she had sent to the blackboard to write a translation in ancient Greek. But applicable to so many things!)
My other favorite, I suppose, is from Chuck Jones, who reported it as something a professor of art told him way, way back in the day. I'm paraphrasing, as I don't have the book here at home with me, but it was along the lines of:
"Everyone has ten thousand bad drawings in him. So the sooner you get them over with, the better off we'll all be."(Which, as Jones went on to relate, mostly just meant: draw; draw a lot; draw all the time. It's the only way to get better, even if you look back on your earlier drawings and think they're "bad". But I think it's also a caution not to get hung up on the idea that you should only draw something if the outcome will be "perfect"; the act of drawing, and then moving on without becoming obsessive about reworking what you've done, is more important.)