Choose one thing and become a master of it. Choose a second thing and become a master of that. When you become a master of two worlds, say, engineering and business, you can bring them together in a way that will a) introduce hot ideas to each other, so they can have idea sex and make idea babies that no one has seen before and b) create a competitive advantage because you can move between worlds, speak both languages, connect the tribes, mash the elements to spark fresh creative insight until you wake up with the epiphany that changes your life.