Shame. People with ADD/ADHD have shameful feelings because they don't understand their actions. They dislike the way others look at them. Other people could call them, "stupid" or "retarded." This isn't always the case.
I volunteer at the local middle school working one-on-one with emotionally and mentally disabled students. There are 2 boys, that I work with, are hyperactive. The one boy is classified as having ADHD. He hardly does any school work because it's too difficult for him to have his attention focused on whatever he's doing. I can see his pain because his classmates constantly make fun of him, and one time he told me he has no friends. He's a lonely boy that wants to be loved but is ashamed at who he is.