The very first law of this Universe is the law of impermanence,
teaching us that nothing is permanent because everything is in continuous transformation.
It could not be otherwise, since the Universe is an ocean of energy in perpetual motion, endlessly expressing itself. 
If we could grasp that fundamental law, we would innerstand that it's useless to hold on to anything. Anything at all.
And we would suffer far less...
We could then gracefully go with the flow instead of fighting it, and find joy in the now moment — the only moment we ever have.