We write in ways that, we generally hope, reflect real life, or at least look familiar to humans. And in life, recurring themes are a recurring theme. We never quite conquer a pet vice or a relationship pattern or a communication habit. We're haunted by our particular demons.

This quote is saying that in life, and also in writing, we often find ourselves dealing with the same issues and challenges over and over again. Our bad habits, challenges with relationships, and communication style might never change. We might never be able to fully break free from these things that cause us difficulty. These problems appear to follow us no matter what we do, and it seems like we just can’t get away from them.