I posted earlier about mutual back slapping (MBS) among the self-published community. But of course it existed long before the recent self-publishing boom, and I came across this anecdote the other day...
The author Shirley Jackson had just published her story The Lottery in the New Yorker, and caused a storm of controversy (which she describes in her essay 'Biography of a Short Story'). In amid the ton of hate mail, and the hundreds of letters asking where in the US this tradition happened (no, really) was a rare letter of praise.
Jackson knew she recognised the name, but she had no idea where from. After trying to remember without success for a few days, she wrote a "complimentary but non-committal" (MBS alert...!) reply and posted it. A few days later she was talking to some friends from California (where the letter from the mystery correspondent had come from) and mentioned the name. Really they said, you had a letter from him? His name had been all over the press for weeks; he had been been acquitted on a technicality of murdering his family with an axe. With a horrible sense of realisation, Jackson went and looked at the carbon of the letter she had written; the last line was:
"Thank you very much for your kind letter about my story. I admire your work, too."