There is a freakin lot to be said for expertise, I gotta say. I'm a fast learner, but someone who's been working in a given field for 20 years can do stuff in a day that takes me a month when I'm learning it from scratch.
I appreciate this is not news, generally, but it's been a long time since I've been brought up against my own lack of expertise so elegantly, and I'm just thrilled to run into someone who *does* have it.