There's the Beginner Phase Querying Disaster:
I put down "Won second place in the My Little Pony poem-writing contest 2003" in my query letter, but then my writing friend told me it wasn't a relevant credit and I shouldn't have included it, and now the ENTIRE PUBLISHING UNIVERSE is going to think I'm some kind of My Little Pony-writing IDIOT and should I e-mail those agents and explain?
There's the Advanced Phase Querying Disaster:
I sent out my queries and wasn't hearing anything back, so in the meantime I kept revising the manuscript, which is now significantly different from the manuscript I pitched in my queries—and today I got a request for a partial, so do I send the old version or the new and possibly better version???
There's the Clusterfuck of Doom Disaster, Agent Version:
I just got off the phone with Agent Z, but then I checked my e-mail and there was a last-minute full request from Agent Y, not to mention the fact that I already promised Agent X I'd get back to him by tonight, except I think I like Agent Y better than both Agents X and Z, and holy crap what do I do?
Fast forward a month or two and there's the Clusterfuck of Doom Disaster, Editor Version:
My manuscript just went on submission, and I'm TOTALLY FUCKED because I tweeted a joke that could possibly be interpreted as a negative review of one of the books Editor A worked on, and I wore the wrong color pants to a conference that Editor B was also attending, and I think Editor C goes to the same gym as my sister-in-law, with whom I am engaged in a blood feud and who will not hesitate to RUIN ME if she finds out?
What all these e-mails share in common is the author's conviction that he/she has a) committed a terrible blunder that is b) extremely urgent to resolve or risk c) a lifetime of failure and regret.
After reading and responding to dozens of these tortured missives (and tracking their outcomes), INTERN has something to report:
With very, very, VERY few exceptions, these situations (or in some cases, non-situations) resolve themselves.
Sometimes it takes a polite e-mail to the right person. Often, it takes even less (that editor whose book you could theoretically be perceived as slighting on Twitter? If you send her an apology, SHE IS GOING TO THINK YOU'RE INSANE.)
Here's something else that INTERN can tell you with confidence:
These kinds of situations happen all the freaking time.
Do you really think you're the first writer who sent the wrong version of a manuscript to an agent? Or went on submission to an editor who has endured the sight of you wearing an unfortunate pair of pants? This kind of thing happens every day in publishing. Agents and editors have seen it before and know how to handle it (often, by saying, "No worries!")
If INTERN had a nickel for every crisis that mysteriously ended up NOT RUINING SOMEONE'S CAREER, she would be a very rich lady indeed.
So please, writers—don't panic. You're doing OK. You really are. Some day soon, you will look back on this disaster and laugh until you cry.