I once accidently sent a query with the subject line 'where were you this morning asswipe?'
TIP: Don't email friends while emailing queries. it's easy to get confused
I shouldn't laugh, but... I can't help it!
Now karma will bite me and I'll do something similar and won't be laughing at all.
One tip I've learned - usually when creating an email the first thing you put in the recipient, right? So how many emails end up being sent half done, or with no attachment, or no spell check, etc due to either premature clickage, or cat-walking-across-keyboard-itis? (I don't have a cat, but I'm willing to pretend I have one to use as an excuse.)
Now with important emails I leave the recipient till last, so whatever happens, that mail is going nowhere until I'm sure it's ready. Get everything else in there, triple check it, spell check it, double check the right attachments are, well, attached.
Then put in the recipient. (Hopefully of course the right one, so you don't accidentally send your frail old granny the red hot erotic short you intended for your publisher...
)