Nuru,
I felt the same as you, til I had people I really, really respected review my work. When lindil questioned my use of a dragon, for instance, and suggested a troll would make more sense, I knew I had believability issues. And I didn't want to give up the dragon! So-- I had to lay a lot more groundwork, and show that the dragon had been around, before he showed up and wreaked his havoc. I had to make the presence of the dragon plausible.
Without lindil's advice I wouldn't have made those changes. But with lindil's changes it is a much better story.
Now, it doesn't work *at all* with someone you don't respect. (Don't bother.)
So-- my advice would be, put a copy of your original story in a very safe place. Then make another copy and hand it to someone you really respect who has a Big Red Pen-- littlemanpoet, at FWW, has a large team of people with Big Red Pens-- and watch them wreak havoc with it. It's a little horrifying-- because you love it so-- and that's why I say put a copy in a safe place so you always have the original.
lmp is on chapter 18 of The Fairy Wife. He's bled all over it! AAAUGH!!! But it is all good. When he is all done, I will "publish" a second edition (the first edtion will not completely disappear.) And it will be much more believable, more bulletproof, tighter, more believable.
Beievability is key to enchantment, which is key to eucatastrophe. So believability is important-- to me, to the reader.
How's that for a ramble? (...join FWW...)