Have you ever done a little bit of research on the percentage of people who start writing books but don’t finish them? Statistics vary, but no matter what numbers you look at, one thing is clear: most people who start writing a book never finish it.

A casual conversation with writers will reveal the same thing, at least if they are being honest. Even the writers who have finished at least one book have almost always started others they did not finish.

What is the root of this phenomenon? Why don’t people finish the books that are so obviously important to them?

It’s not because people are too busy or because they don’t want to finish the books. It mostly comes down to fear. Writers are afraid their books won’t be good enough.

But what does a “good book” look like, anyway? Who determines the rules about what makes a book good or bad?

The dirty little secret of writing and publishing is that it’s mostly arbitrary. Sure, a book needs to be organized in a coherent way, written well, and be edited. But beyond that, it’s mostly conjecture. The so-called critics and experts are just people with opinions—and even those opinions can change at a moment’s notice depending on cultural trends.

There’s nothing to fear here. So remember the mantra that business leader Sheryl Sandberg likes to repeat: “Done is better than perfect.”

The next time you feel afraid or want to avoid finishing your work, tell that voice inside your head to take a hike. It’s trying to sell you the lie of perfectionism. It’s also trying to keep you from finishing the book that can bring an amazing amount of joy to you and your readers.