"Why yes, I AM brain-damaged!
How astute of you to notice!
Were you run down by a car too?"
(I thought about saying that, but instead I said, "thank you for your help," with a smile.)
NOTE TO SELF: It is probably NOT a good strategy to voice your thoughts to stay focused while in public.
Ironically, this person seemed very kind and helpful when I was having difficulty focusing. I was looking for corn starch in the "flour" section of the grocery store, but struggling because I kept getting distracted by what I saw and having to re-focus on what I came to get. I have found that my faulty short-term memory works a little longer if I hear myself say what I need to do, so I was speaking to myself when a store employee overheard my self-talk and pointed me in the right direction. I truly appreciated his help, and told him so with a smile. He muttered loudly about who lets brain-damaged people out ... I didn't hear the rest, and I pretended I heard nothing at all. I wanted to say my line above, but I knew better than to antagonize him.
Brain-damaged people like him might behave irrationally.