There is a Margaret Atwood poem called Heart. The first three lines go like this:
Some people sell their blood. You sell your heart.
It was either that or the soul.
The hard part is getting the damn thing out.
I feel like that so often. An art piece will sit propped against the wall, sometimes for weeks until I figure out why I started it and how it needs to be finished. This one is still sitting there with all its lovely texture.
Here is the link to the full poem. http://www.theguardian.com/books/2007/aug/18/poetry.margaretatwood