A lot. So called "hyperfocus" is a hallmark of ADHD. Most people might think of ADHD as can't concentrate or get distracted easily due to the "attention deficit" moniker but in reality ADHD is badly named, and it's much more an inability to direct your attention. Hyperfocus is the the opposite extreme of not being able to concentrate and getting distracted easily as you find yourself unable to switch your attention away from what it is you're interested in. This is especially problematic when you have other activities that require your attention like filing your taxes, folding the washing, taking out the trash and doing the dishes as you tend to not be able to get your brain to accept engaging in those tasks and often some of them wind up left undone. Sure you made progress in whatever the latest obsession was, but you find relationships with those around you strained with this constant back and forth of "you left dirty dishes in the sink again last night, you forgot to take out the rubbish again, and when you fold the washing don't just fold the washing but also put it away please" and all you want to talk about is the cool new stuff you learned last night.
Edit: I find it quaint that people can consider how hard they should push themselves and have the option of doing it or not. I get sucked into it no matter what.
This line of reasoning was precisely why I ended up missing a diagnosis of ADD by 17 years. It was because the specialist said that since I could pay attention to the things I "liked," a diagnosis was not appropriate for me. My life could have turned out a lot differently if I was medicated sooner.
I believe that people should no longer treat AD(H)D as an acronym. It isn't accurate to call it a chronic "deficit of attention" and hyperactivity isn't necessarily a symptom. It's unfortunate that the name has to stay for the purpose of recognition in the face of the new evidence we've gathered in the past few decades.
>Why did they disqualify you based on being able to focus on things you like?
Lack of knowledge on the part of the person assessing them. Some people who go for diagnosis wind up going to people who don't specialise in it and they wind up being told these kind of things.
ADHD is an "executive function" disorder -- it's hard for your brain to consistently focus on doing what you "want" it to do.
It's stereotypically thought of as an inability to focus your attention ("can't sit still and concentrate"), but it's also an inability to stop focusing on something you know isn't in your overall interest/plans.
