The Achilles' Heel of a Story

I was thinking about this, how every other story I write has some issue with it. Wouldn't it be great if we could all write a perfect first draft? One story I wrote this month had a nagging problem with the intro; it was kind of rough and unclear, and took a few rewrites to get it right--well that's the hope, at least.

While other stories, the ending simply doesn't hold up, and that has to be rewritten--or worse--the ending isn't written at all and the story sits there in USB purgatory. Oh, and on an unfortunate note, my USB stick broke and all my "in-progress" stories were lost. Some I was able to recover from emails, but yeah, I'm not paying hundreds of dollars to get them off a broken USB. So lesson learned: finish your stories...or do a better job at backuping. 

Anyway, there always seems to be that one issue, the Achilles' heel that prevents the story from being "good enough" to allow editors to see, or could potentially lead to the death of the story (literally, if you're like me and fail to backup).

So, to expand this out to you few followers, do you have an Achilles' heel in your story/stories? Doesn't have to be an actual issue with the story itself; low self-esteem about your writing can also be an Achilles' heel.