I've been writing a 1000 words a day for almost six years. And on any given day, 90 percent of what I write is terrible, incoherent nonsense that makes me wonder why I bother, why anyone would pay me to write a book, or whether or not I have something interesting to say. It's a mountain of shit.
But if I continue to write, if I keep typing, and shovel more and more shit, I'll find an ounce of gold. It might be a sentence or even a phrase. Say that you have an ounce of gold. You could use it to make jewelry, gold wrappers for chocolate, or cut it up into flakes and brew some homemade Goldschlagger. The same applies to the ounce of gold you dig up in that mountain of shit. There's a reason Anne Lamott refers to early writing effort as shitty first drafts.