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.
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.