macdicilla:

There’s this one Neil Gaiman interview where he says that the character of Crowley was supposed to be more shy and diffident, and all I can imagine that happened is that Crowley showed up and begged him and Terry not to expose him like this, and to make him cooler.

Also he definitely had a hand in casting the radio play. Radio verse Crowley is what Crowley wishes he were like. I bet he listened to a lot of Peter Serafinowicz recordings, to the point that Aziraphale got suspicious and asked him who this Peter Seraphim was. And then Crowley just breaks down like “I wish I had a voice that cool.”