When I was a teenager I decided to learn German. It did not last, because I got freaked out reading the first chapter of my self-teaching book, in which all the dialects were described. It gave an impression that even if I would learn everything that was said in this book nobody would understand me anyway except of a few dozens of people in a certain area. It was really discouraging, especially for a Russian native speaker, who is not used to the idea of many dialects.