When most people thinking of Attention Deficit Hyperactivity Disorder (ADHD), they may picture someone who is fidgety or someone who gets easily distracted. But some people can have ADHD without even realizing it, and some of the signs of high-functioning ADHD can actually be surprising. The disorder can involve more than just the inability to focus on one thing at once, and it can affect areas of your life that you might not realize.