This issue cropped up again because there was a rejection in my email inbox this morning in which the editor opined that my story was not "sufficiently distinct" from other mythic retellings. I was slightly tweaked by this, as I occasionally am by rejections, even after accumulating well over 1,000 of them and having been a (co-)editor on almost a dozen book projects.
The irony in this particular case is that the story was a reprint sub of a piece which had originally run in a major market, then appeared in two Year's Best volumes as well as accumulating a number of other YB Honorable Mentions and strongly positive reviews. All of which means absolutely nothing if the story is not to the editor's taste. As kenscholes reminded me in chat, rejection is always arbitrary and subjective.
So many of us (myself included sometimes) take rejections personally. They're not personal. A rejection is that editor's reaction to that story on that day. Nothing more, nothing less. To read a judgment about one's own personal worth, or even the value of the story on the page, into that is a mistake. Very human, very understandable, but still a mistake.
Sometimes I need to remind myself of this.