"Because it's you," Aziraphale said tightly, wishing he could make Gabriel calm down. He looked quite like Aziraphale imagined he himself had looked at his and Gabriel's first meeting: tightly wound, ready to jump at any potential danger. If Gabriel went into hysterics, he had no idea how he would even begin to control him.

Well, he did know in that he knew he wouldn't be able to, so there was that.