My first cease and desist
A cease and desist letter is every entrepreneur's right of passage. I found my first.
[Context: Before a record-breaking 2004 episode of Jeopardy aired, I received an audio clip of contestant Ken Jennings losing, so I published the audio on my news site, whose ad revenue helped me pay for grad school.]
Sometimes an angry letter is an affirmation. (Major League Baseball sent us a grumpy letter ten days after we launched Fancred.)
Other times, in my first case, it's a free lesson from a lawyer. I didn't have $10 to my name when I received this email, but I'm glad the lawyer was understanding and let me off with a warning.