the copycat; busted!
"We have one microwave for our entire floor, saw the note, thought we worked with crazy people... One of us said 'Hey! We should post that on passiveaggressivenotes.com!' and lo-and-behold, we found the SAME NOTE on your site.
We have no idea who sent it, but we hope to start a post it chain of communication through your site and crack the code." —an anonymous submitter in Brooklyn