It's really quite beautiful Couple of examples:
The Unknown The Unknown
As we know, 
There are known knowns. 
There are things we know we know. 
We also know 
There are known unknowns. 
That is to say 
We know there are some things 
We do not know. 
But there are also unknown unknowns, 
The ones we don't know 
We don't know. 
—Feb. 12, 2002, Department of Defense news briefing
A Confession Once in a while,
I'm standing here, doing something.
And I think,
"What in the world am I doing here?"
It's a big surprise.
—May 16, 2001, interview with the New York Times