For one thing, I think you exaggerate how stressed out he was. For another, I think you read to much into the clip of his rant. I mean, it is a stretch to say that because he likes to holler, then he is not up to facing a crisis.

Facing crises might be Bush's strong point. Of course he has some important advantages. His decision making is unencumbered by the truth, and anyone who disagrees with him is wrong. Those traits make it easy for him to be decisive.