Good quote. I should track down the book.
Years ago, I saw a write speak (I think it was Jane Yolen, but I could be conflating different events), and she noted, when someone asked about becoming a writer, that, "a lot of people say they want to write a book, but they actually want to have written a book." They want the success, not the work. But the fear of being told you're not good is also a huge demotivator.