Transiency
We should find perfect existence through imperfect existence.
That everything changes is the basic truth for each existence.
This teaching is also understood as the teaching of selflessness. Because each existence is in constant change, there is no abiding self.
When we realize the everlasting truth of "everything changes" and find our composure in it, we find ourselves in Nirvana.
Because we cannot accept the truth of transiency, we suffer.
We should find perfection in imperfection.
Pleasure is not different from difficulty. Good is not different from bad.
So to find pleasure in suffering is the only way to accept the truth of transiency.
Whatever you may feel about it, you have to accept it. You have to make this kind of effort.
If you are suffering, you will have some pleasure in the teaching that everything changes.