Wimsey is going to get a HECK of a lot more than he anticipated, isn't he? Crowley isn't rabidly viscious (unlike Haster and Ligur) but he's quite clever, and he's definitely enjoys poetic justice/revenge. He and Constantine share a 'do unto them before they do unto *us*' attitude, and since Crowley is a demon, he's much more likely to create instant mayhem.

On the other hand, Aziraphale can step on Crowley the way he can't on Constantine. John doesn't *care* what Aziraphale thinks of him, and Crowley actually does. And John is a *lot* more stubborn and viscious in his anger.