Sounds like fresh clean water for this fish... There's not much in the way of really good developer training out there compared to how it used to be. The MS Basic manual that came with my TRS-80 CoCo was a pleasure to step through one chapter at a time, by the end I could build my own rudimentary GUI! Age of 9, I should mention also.
I kinda imagine that Valve as a company is a bit like resistance leaders, eli, isaac, alyx, barney, all a bit crazy but allways getting out alive.
People who cultivate inner motivations have the capacity to work harder than artificially imposed. Cultivating that is an epic leadership skill. I can only assume that Gabe Newell was really not a fit in Microsoft...