The Bhagavad Gita has two amazing words in Sanskrit, to describe the world.
One is ashaashvatam – which means impermanent.
The other is dukhaalayam – which means sorrowful.
If we think back to most (or all) of our possessions and experiences, these two words sum them all up. What we think brings great joy to us today, eventually results in great unhappiness. Because those things either make us want more of the same. Or they are things that we realise we cannot cling on to forever.
The reason the world is summarised this way, is not at all to dash our hopes, or to make us morose and depressed.
Instead it ably reminds us of the inevitable, and aims to shift our focus to how we must live.