Authors speak of their works in progress in a variety of ways: with excitement, with concern, with joy, and with anticipation. There's a feeling that comes with starting a new manuscript that for me is an odd combination of thrill and dread.
It wasn't always that way. When I first began writing, I just wrote, and when I finished that first MS, I was thrilled to be "done" with a "book." Wrong on both counts. It certainly wasn't done, and it never became a book. It's just a collection of words somewhere on my hard drive. With subsequent projects I've become more ... maybe the word is jaded, but I'll say realistic. I know how much work I'm taking on when the germ of an idea starts bouncing around my brain, and the joy is somewhat tempered by that.
Yes, it's fun to create characters, set them into a plot, build an interesting setting, and write it all down with good dialogue and exciting details. But it's no picnic, and those who picture writers being "inspired" to set down the story all of a piece and then going, "Ta-da" haven't got a clue.
Work in progress is a telling term. There's more work some days than progress, but when the progress happens, the work becomes a labor of love.