Mmhm. I admire people who can finish a whole 20+ chapter story before they post anything. If I waited that long, I wouldn't have anything to post.
As her proofreader, I can assure you that this is true. XD
I think it's why I love to write one-shots, anyways, when it comes to fanfiction. I don't have to worry about hitting a block, or losing interest. I write one chapter, maybe 10 pages or so, and it's done, I can move onto something else. I do feel bad when I can't finish a fic, though sometimes I can't avoid it for the sake of (whatever remains of) my sanity. And this is where the difference between OC and fanfiction comes into play for me...
It's easy for me to come up with a one-shot when the characters are already known. When they don't need a background, because the background, or most of it, is already there. It's hard to develop a one-shot with OCs, considering you need to explain their background for the story to make sense. Sure, I could pull off some OC one-shots, but my characters tend to have complex backstories I can't necessarily put in one chapter. I may not lose interest TOO fast, but I can't, for the life of me, write one or two chapters and lose interest, because if I'm writing, I have my beginning and my ending set in stone. If I lose interest, it might be after 9-10 chapters or so, because I need filler material, or characters won't cooperate with my setting anymore.
So maybe I could plan some more, if I wanted to finish OC stories.