To contemplate impermanence on its own is not enough: You have to work with it in your life. Let's try an experiment. Pick up a coin. Imagine that it represents the object at which you are grasping. Hold it tightly clutched in your fist and extend your arm, with the palm of your hand facing the ground. Now if you let go or relax your grip, you will lose what you are clinging to. That's why you hold on.
But there's another possibility: You can let go and yet keep hold of it. With your arm still outstretched, turn your hand over so that it faces the sky. Release your hand and the coin still rests on your open palm. You let go. And the coin is still yours, even with all this space around it.
So there is a way in which we can accept impermanence and still relish life, at one and the same time, without grasping.