I agree with some of the people already spoken. Personally, I'd rather bring new perspective than repeat, so here's my answer: Mastery. It feels fantastic to hear professionals discuss aspects of their field with each other. I might not have the same grasp on the idea as they do, but the sheer depth of conversation drives me crazy from joy. I'd listen to Stephen Hawking discussing fringe physics theories with another expert if it costs me my diploma. I'd listen to Eminem discussing the philosophy of rap and his perspective on it as a white rapper if I get fired for it.
That's so true! I once listened for hours an engineer talk about wood-cutting technologies in Sweden, how we're not really doing it right in Canada, and how he set up a paper-processing plant in SE Asia to help develop communities. He worked 30 years in the industry and it was fascinating to listen to. Who knew a conversation about trees and paper could be so interesting.