I like, but its not my favorite.
My favorite is summed up here:
Picking a fight with The Bloggess and other big PR mistakes | BabySteps | a Chron.com blog
The TLDR version:
PR person sounds out a stupid, blanket e-mail. The blogger writes back with a sarcastic e-mail and a picture of Wil Wheaton collating paper. Naturally.
Said PR person hits reply all with "bitch" to which blogger did not appreciate. E-mails him back saying that its inappropriate. He vaguely apologizes but more thinks she should feel special to be relevant enough to receive their e-mails in the 1st place.
Blogger decides to teach him something of her relevance by tweeting the entire thing to her 168,000 followers.
Hilarity ensues.