I’ve taken metros in cities around the world. Some made getting from point A to point B feel like a breeze. felt easy. It was a smooth ride through tunnels. In other cities, a simple transfer felt like a word problem on an SAT test. It was like a test in understanding directions. At some point, after many platforms, transfer corridors, and escalators, I stopped judging a system by its size or fame. Instead, I began to judge it by something simpler: