I have a perfectly healthy lifestyle - I run 5 days a week, about 40 miles total, eat healthily and sleep well. During my runs (which physically feel painful) I have few moments of clarity in my head. Other than running though my mind has a thousand thoughts all at once that I cannot control...
I tell a story, interrupt myself, get 6 levels deep and then essentially have a stack overflow and can't recover to my main point that took me down that spiral. Nobody can follow my thought process. What I do know is that my mind is stimulated by strong feelings.
I sit at my desk to do work, notice a story about the DOT / airlines soon banning ESAs and proceed to research the legal authority according to the ADA and other provisions in U.S. Code. I waste a lot of time thinking about the stuff I need to do, but I can't get myself to do it. So I don't do anything that is fun for me, nor the work I need to do itself. Only under immense stress due to deadlines (and the potential negative consequences of failing to deliver) I can force myself to crank out work that is of reasonable quality. This is how I went through all of high school and college for example. I was completely sleep deprived as a result.
Never in my life have I been able to finish reading a book for school - I'm bilingual (learned English as a second language), but this isn't a language problem for me. I simply don't know what I read at the top of the page when I get to the bottom. I read incredibly slowly (I have to imagine hearing someone speak the words - this is called subvocalization). If I focus on reading for fun it will probably take me 3-4 months to get through one fantasy books. If I can read 3 books in a year I had a very good year.
At a dinner in a restaurant I cannot pay attention to my friend (or date) in front of me, because other conversations around me draw in my attention and trigger my brain when interesting subjects are raised.
I am not able to focus without extreme stimulation and am completely at the mercy of my brain / mind. This means I can't listen to people well, I get impatient and interrupt people at inappropriate moments.
Yes I'm high-functioning and I do well, I have a crazy amount of energy, but this isn't a healthy way to live. I am not lazy, but my mind is. I am convinced I'm only operating at 20% of my true cognitive potential and output potential.
For these and many more reasons I will be seeking diagnosis for ADHD (or ADD?) soon.