Having a label helped me a lot for similar reasons to FG - I could capture my demon. Looking back at my life and the way that things have gone, I can also recognise ADD behaviours there (indeed, recognising ADD behaviours in my school reports was a key element of the diagnosis). This gives me power to forgive myself: ADD is not an excuse for my poor performances in the past, but I've spent too much of my life thinking of myself as lazy and weak. I feel that I understand better why my education was so skewed towards things I liked, or why I flit from subject to subject, or why I will focus on interesting things to the exclusion of all else, or why I have such an appalling sense of the passage of time. Recognising these things (rather than blaming myself for them) has helped a lot.
I'm normal on the surface. Whatever demons I carry with me are my business, but I'm approaching 40, single, childless and seem to be attracted by, and attractive to, men 15 years my junior. Make your own conclusions, then keep them to yourself! ;o)