Your diary is actually what got me thinking about this subject. I certainly didn't mean to have it seem directed at you! Consider yourself the inspiration, not the target :-)
I have abandoned two novels, and am working on the third - this one I will complete, because I'm pretty happy with it. So I haven't completed any novels yet. (This is the novel whose first chapter I've posted on my personal site.) I didn't start writing anything I actually liked a week later until grade 12, when I started my current novel.