I move outside my comfort zone because I know it is the only way to grow.

The zone never actually gets abandoned. It gets larger, which is a much friendlier way to picture the whole business.

The first time you drove on a motorway your hands were locked at ten and two and every lane change was an event with a heart rate attached. Now you do it while half-listening to the radio and thinking about dinner. That territory got absorbed. That's the real mechanism. You go slightly past the edge, it's uncomfortable for a while, and then the edge is somewhere further out and the old ground is home.