The ADD-ers secret smile!

I am wondering if others have noticed that when the ADD person in a relationship gets the other person upset, angry, etc. He/she has a slight smile. 

It seems to me that he is enjoying himself (a) because he caused me upsetness; and (b) because he likes seeing me that way.

When this happens in my relationship my anger is very hard to control: I could hit him really. This and his defensiveness are the worst symptoms of his ADD for me.

I would be most interested to know about the feelings that others have when the 'secret smile' occurs in the other.

(Dr. Phil put me on to this particular kind of smile some time ago in relation to another problem).