I've seen Petraeus give many briefings over the years, and it's a bit like watching a magician at work. Even though you've seen the trick before, and you know the patter, you still get mesmerized. He has the ability to make people believe the impossible might be doable, after all.
A warrior and a scholar, Petraeus is sometimes jokingly referred to as a water walker, since almost everything he touches seems to turn to gold.
Joke's on us, I guess.