Here's a valuable lesson: when you're editing something for submission, don't send it as soon as you're done.
I finished up some edits on a story (tentatively being called "The Academy" although I don't really like the title) that I'd written with a certain anthology in mind. I formatted it up nice, typed my cover letter, sent the manuscript.
And, about an hour later, lying in bed, I thought of two killer new scenes that would have been great in it.
So it goes, man. So it goes.
Ah well. Wish me luck, anyway.