One thing I discovered - Training is a means to organize your thoughts so the communication is clear.
How I've realized this is because I have this innate ability to recognize and use my instincts, based solely on experience to design whatever it is that needs to be designed, but without all the language. Basically, it's second nature to me and to justify it can sometimes be a task in itself. Artisans don't really need to explain themselves or justify their work unless they're in the selling stages. Since usability has an art and science, on my part at least, the science and the art of communicating that science is more clear, simply by taking a training course on a heavy subject that takes three days to cover.
Now there are words and groups of words that form an explanation of how and why usability works. Knowing the why is half the battle. Explaining it to anyone else other than yourself, in an objective, non-opinionated way is the other half.
So for those who are still apprehensive into taking extra courses, let me just say that if you're not open for this kind of learning and relearning, you really have no business in the usability field. Actually, to take this further, those who think they "know-it-all" will find themselves stuck when all of a sudden they discover they don't and now is in need of additional knowledge or resources, but it is inaccessible because you haven't bothered to take the time to learn more than you already know.
For any kind of success, in business or in life, and in this case, user experience design or however you want to call it, growth is the key.
Take that extra course. It will change your life.