The average child with ADHD hears 20,000 additional critical or corrective messages before their 12th birthday, far more than a kid who doesn't have ADHD. That criticism can have a significant impact on the self-image and self-worth of a person with ADHD.
People with ADHD have a hard time being aware of social appropriateness and interactions, so they end up being socially ostracized and, as the saying goes, they are the last picked but the first picked on. Consequently, most people with ADHD grow into adulthood with a profound feeling that they are less than everybody else in some way. They feel uncool and unwanted, and sometimes even profoundly defective. The term you'll hear very commonly is "damaged goods," and that the person with ADHD feels generally incompetent in the world.
The resulting shame and guilt often produce a situation in which positive feedback just slings right past them. They never even notice it. They're much more in tune to the negative feedback they get. Consequently, the shame almost always dominates all the other emotions. As Freud said, "Shame is the master emotion." It's the only emotion that doesn't seek expression and it can determine whether other emotions get expressed or even acknowledged and dealt with.
[Free Handout: Get a Grip on Tough Emotions]