Or is it?
I have at least four completed WIPs and three that are proposals (synopsis and first three chapters of a book).
But I've learned one thing in my many years of writing and that is never give up on a WIP.
Maybe you've shopped it around to several publishers, maybe you've ignored it for several years, or maybe the market isn't right for that novel, but whatever you do keep your WIPs because you're never really finished with them until the book is published.
Pull out a WIP every once in a while and see how much you've grown as a writer and what you can do to tweak the story that would make it more publishable.
Right away I could see what many of the problems were in that book. There's a lot to be said for letting your work sit for a while. A week, a month, or even a couple of years can really make a difference in your writing skills and the critical eye with which you read your own work. I'm very grateful that I never gave up on that story because I eventually sold it. And look what a beautiful book it became.
Sometimes when I pull up an old story on the computer and start reading I wonder what in the world I was thinking. Sometimes I've found flat characters or characters so over the top that they are unbelievable or worse, uninteresting. And then sometimes I've found huge holes in the plot. Yikes! I'm very glad that I can now take out some of my old WIPs and work on them. My stories are like old friends just waiting for me to get reacquainted and help them grow into better books.
How many WIPs do you have waiting for your attention? Do you work on more than one at a time? Have you been surprised sometimes by how much you've grown when you've taken another look at your old story/friend?