I've discovered a problem with my Twitter account... sometimes people read it.
I recently had an e-mail exchange with a magazine editor, and, me being me, I cracked a joke in my e-mail to him. The problem, though, was that I sent the e-mail at 2 in the morning on a night that I wasn't sleeping well. I woke up the next morning worried that the tone of the joke was a little harsh. So, I posted as much on Twitter, saying that I worried about being "snarky".
Later that day I got the editor's response to my questionable e-mail, and the first line was "Wow, that was snarky." I started to panic that I'd really goofed this one up until I scrolled down the message and saw "Kidding! (I saw your tweet)."
A very good joke, and a reminder that every great once in awhile people read what I write.