[Quiet Man Cometh]

It's surprisingly easy to miss stuff in your own work. I've proofread a piece four times and still found an error in it when I printed it out to read again. I think it comes from having written the piece, when reading it over the writer may read more from their memory of what they wrote rather than directly from the page, which a new reader would have to do, and therefore miss some of the mini-mistakes like that.