Look down at your feet. If you are wearing two different shoes, most likely you have it.
Really, I went out this morning. When I got to where I was going, I noticed my shoes felt funny. I had on two different sneakers and it was too far to go back and change them.
So, I traipsed through the mall with 2 different sneakers. one regular and one high top (concealed by my pants leg) At least they were a similar style and color (one plain, one with gray trim).
The ADD comes in because I was changing from one pair to the other and got distracted.