People, problem, idea.
In that order. I like finding interesting, painful problems that face a group of people I care about, and take a crack at solving it. I subscribe to the idea that founders who deeply empathize with the people they serve are best suited to succeed. The problem spaces I'm currently exploring are (1) the flow of human capital and (2) the growth of human capital.
My career decisions follow this mindset; I owe it to the people I will one day help to be as prepared as I can be, so that on that day, I may perform to the best of my ability.