We know that someone who has channeled his anger into something constructive has not had a cow. How do we know these things?
Empathy - that is, caring about people and acting responsibly on that care, not just for yourself, but for others - this is something that Barack Obama understands very well. He was a professor of constitutional law at the University of Chicago for ten years. As an expert on the Constitution and on our family values, he understands very well that the country is fundamentally about caring for one another. The day after his speech, he was interviewed on CNN, and Anderson Cooper asked him what patriotism was. He said patriotism begins with caring for one another.
You see Bill Clinton, and you say: Oh, this guy cares about me. Hillary Clinton isn't the same way. You see her, and you don't necessarily have that view. She's trying to achieve the same thing without the voice and the body language, and she's having a harder time doing it. But when she's effective, that's what she's effective at.