Having read this thread,I cannot help but wonder what the "Aha!" version may mean.I have always known of the "Too late" version which arises whenever anything is,well,too late.I have always used and heard it used for trivial things or to trivialize big things missed.My parents-now in their 80's use it,but I and they have no memory of their parents' generation using it.The dance theory seems good:"what a shame,you are too late for a dance as I now have a wooden leg...see!".I am from Melbourne,Aus.and the "Too late" version may be Hemispheric,as others have said.