Last weekend, one of the world’s greatest tennis players, Novak Djokovic, won his 23rd major grand slam single’s title—the most for any male tennis player ever. Such an achievement requires incredible sacrifice, pain, and hard work. And a large measure of self-belief. And a whole lot of talking about oneself. As I watched this feat, I wondered, “When does the self-confidence needed to accomplish great things turn the corner into self-promotion?” My thoughts went this way because I recently co-wrote a book. And I am proud of a job well done. I’m celebrating that achievement. And I’m telling others because, well, I believe the message is worth sharing. After all, why write the…