Condoleezza Rice thinks reflecting on mistakes "not a very fruitful exercise"

This is a fascinating exchange from the New York Times Magazine interview of former Secretary of State Condoleezza Rice:

I’ve read that people consider you almost incapable of admitting a mistake. What do you consider to be the biggest of your career? 
You know, I’ve done pretty well. I don’t spend a lot of time dwelling on the past that way.

You can’t think of just one? 
I’m certain I can find many. It’s just not a very fruitful exercise.

This is a very smart, accomplished, experienced person saying out loud, in print, that "dwelling on the past" isn't useful. This makes me think about what it must be like at the highest levels of public office, where every decision is second-, third- and fourth-guessed, where 35-40% of the people reflexively disagree with any action you take. It's a place, even years after leaving, where reflection and self-criticism is difficult even for the best and brightest.

Consider Robert S. McNamara. Widely vilified for his role in Vietnam, it took him thirty years before he wrote "In Retrospect," in which he finally came to terms with the consequences of his decisions while Secretary of Defense.