pity and inspiration
For me the most obvious time this happened was I used to give trainings about how to make things accessible when I was an undergrad in college. I would give the presentation all about ways to be more accessible in programing and also teaching about basic disability 101 type things. At the end of the presintation some one would say "you have dyslexia and ADHD and your in college I couldn't do it lets give her a hand." One I do many other things other then just going to college all of you also were in college yay you, you are doing amazing things. In that instance it ruins any ability to tell if they are impressed I exsisted or think my presentation rocked.
The same thing happened when I brought in a speaker with a disability and all the people were asking questions about her specific disability and not all her achievements. This is a high powered person who has done many things and all you ask is disability specific questions and marvel that the person could talk. Not that the person had achieve some really awsome things. I think it also sets the bar low, why do cool things if just by getting groceries you get told you rock.