That progression over the long term and the short term is part of the draw. To be a little better now than before feels very rewarding. It's like climbing a mountain with many summits. There is always something more to strive to, yet there are many peaks that signal success. To be clear, a mountain has one summit, and it is the top. There are few activities you can compare the past to the present yet running with its clear numbers says unambiguously, "this is where you are today, and that is where you were yesterday."