I have this idea for an image. I can see it when I close my eyes. And it's not really that great of an idea; a cliche actually, almost kitsch.
It's producing an acceptable image I can see when my eyes are open that's proving to be the problem. If I can ever get it right, I can get it out of my head.
Right now it's not working ... not even close.
I'll have to put it away and come back to it later. Maybe then I can get some work done in the meantime.
The last time this happened I had 20 years of failure before I finally got the image I wanted. I don't think I've got that much time for this one.