Which are the symptoms of Attention Deficit Hyperactivity Disorder?

Starting or wanting to start a new project or activity and getting halfway done and stopping and not going back to it for a while.

I was diagnosed with ADHD at the age of nine, my mother tried every possible alternative she could, even a couple of kooky ones, before relenting to the intense pressure from my year 4 Primary school teacher and allowing me to be prescribed Ritallin. As a child all the way up until the age of about 21 I was completely unable to focus for extended periods of time (unless I was on Ritallin, which I stopped at 14 and in the process of being prescribed again).

Regardless of what it was I was trying to focus on. It could be a test, it could be class, it could be my favourite TV show, it could be my favourite video game, it could be my mother talking. It didn't matter, after maybe ten minutes I would be completely lost in my imagination or inner monologue, while still maintaining eye contact and nodding to the person speaking to me. This symptom I seem to have grown out of somewhat, my major issue now is the effect ADHD has on my short term memory as an adult.

I seem to constantly forget to do parts of small jobs while doing them. I'll empty some grey water at work, but then forget to close the tank, I'll clean and flush out the coffee machine, but forget to empty the water tank located on the back. These are menial tasks that I do almost every day and I still forget to do steps in these and other tasks that I do very often at work. It's frustrating beyond belief because I'm otherwise a very competent and, I'm told, intelligent person, so my co-workers don't really cut me any slack when I do things like this.

If I could remove one symptom, it would definitely be the short term memory issue.

Being disorganized,inability to stay on task, starting 5 projects at once and not finishing any.