That joy is transient and ultimately in its transience a cause for suffering. Perfectly fine if you take it for what it is, but not something to cling to. 'Life

That joy is transient and ultimately in its transience a cause for suffering. Perfectly fine if you take it for what it is, but not something to cling to. 'Life is suffering' is kind of the whole deal of Buddhism - first, it teaches you to recognise how bad the problem really is, then gives you mechanisms for solving it (detachment).