We don't often like to think about impermanence, especially our own.
But this turning away from impermanence leads us to believe and cling to permanence.
Something good happens and we cling to it hoping it will last for ever. We fear that it might disappear, so we suffer.
Something bad happens and we feel that it might be permanent. We fear it will never end, so we again suffer.
If we realize and accept the truth, which is in both cases the situation is impermanent, then we do not suffer. As usual, the situation doesn't cause suffering, its our unwise habitual way of thinking about the situation. Its a lack of clear seeing, a lack of mindfulness.
This is why its important to contemplate on impermanence. As the saying goes "This too shall pass".