DX is tough in the mental health arena. We're mostly just treating symptoms and the DX is essentially based on that. You could have a different dx based on what doc you see, or when you see them. Symptoms for different conditions can look very similar, and it's up to the judgement of the doctor what label to place on you. (It is important for the doctor to have a diagnosis for you because without it, he/she is not getting paid) For many of these symptoms, the treatment is the same.

The doctor works with you and you make a plan to help minimize symptoms and episodes. I think it is important to have a dx because it can give guidance to other health practitioners. For example: I go to my primary care and tell him i'm depressed. He wants to provide a script for Zoloft. He sees that I have a dx of Bipolar Disorder I and realizes that the antidepressant may be a bad idea.

If you're getting the right treatment, I don't think the DX is very important. It's all a spectrum anyway. If you ask me, everyone is a bit bonkers. Some are just better at hiding it.