You know like arbitrary lines in the ground, or big round numbers, or some construct someone comes up with that folks latch on to? Usually completely meaningless in the grand scheme of things?
In the last few days, I crossed my first state line, passed the 100 mile mark, and have climbed the equivalent of one Mt. Everest.
Of course if you push too hard to make one or more of these milestones, and end up in a motel for days popping pills and icing your leg, they may be meaningful - Just not in a good way.