By chance saw a tv programme 9 or 10 years back about kids with ADHD and suddenly understood exactly. I also realised just how crap the media and popular view of it is. Found out that there were an awful lot of other habits and symptoms that can be a part of it and could mentally check off quite a few. Suddenly I wasn't confused about why I did a lot of the things I did, all the way back to early years.
Internet research would probably have had me give up if I hadn't seen the documentary. Half of what I found was "ADHD doesn't exist" or made up junk to sell a book, or a diet or "amphetamines are terrible" as it was the height of the media theme of too many diagnosed or conspiracy to sell Ritalin. Got past that to medical and quality resourses and discover the different degrees of ADHD or even that there's several forms and you don't even have to be hyperactive and bouncing off walls.
Started to understand where my habits failed and why. Started to understand why I couldn't fix a few things most people find laughably easy.
Pushed for diagnosis (took a while), got medication, realised they're not a miracle reprogramming cure. They fix many of the faults in the brain, but don't cure all the bad habits you developed. Been working on better habits since.
Wish I'd had medication and awareness through education, though I got OK results by the luck of being bright. My 20s would have been easier before I started to figure out decent systems to work around my weird. :)
Edit: Sorry didn't realise I'd written that much!