There several posts I intended to write over the past two weeks, but I had to write instead. That is, complete a book that was past it's deadline. (That sounds so much better than "I'm late!")
Which reminds me of conversation I had with an editor, Meredith Mark, 20 years ago or so, regarding a book that I was going to write, then waited a year to start. We were discussing the book and I was bemoaning the fact that I felt I really should have written the book a year earlier. Not that it was due, or even scheduled. But I finally had started writing it, and Meredith pointed out that perhaps the reason I hadn't written the book sooner was becauase I couldn't write it at that time.
I bristled for a second, thinking she was impugning my ability, then realized what she was saying. "Yeah, you're right," I told her. I wasn't the same person a year ago."
Which I bring up to support some advice I offer some writers: Don't get too bent out of shape if that book (or story, etc.) just isn't coming along. Maybe you just can't write it now--but you will be able to write it later, when you're the right person.