It doesn’t matter how many words I’ve written, or that I’ve finished an entire book–or that I’m almost halfway done with the first draft of a second–I still get a mild panic when I sit down to start a new writing session. It could be the start of a scene or chapter, or it could be picking up where I left off in the middle of one, but either way, I still have to give myself a pep talk right before I begin.

What is it about a blinking cursor or a blank sheet of paper that instills fear into the...