Children with ADHD exhibit poor executive functioning. They lose things, get overwhelmed by simple tasks, and are late: late for lessons, late with homework, and late starting assignments. This leads to them being thought of as either lazy, stupid or difficult (or a mixture of all three!) ADHD children are usually none of those things – it just looks like it!
These difficulties can persist into adulthood and affect important life choices. The key thing is that it can be managed with the correct strategies.