Nothing about this makes sense to anyone who hasn't done it before. Uphill, into the current, through water that's actively trying to push you back to where you started, and somehow that's the whole plan. That's always been the plan.
It doesn't ask whether it's tired. It doesn't stop to wonder if this particular rock, this particular rush of white water, is the one that finally wins. It just goes. Again. And again, until the river runs out of ways to say no.
Some things aren't built to make peace with the current. They're built to answer it.