A quote from Zen master Shunryu Suzuki

The basic teaching of Buddhism is the teaching of transiency, or change. That everything changes is the basic truth for existence. This is the true teaching for all of us. Wherever we go this teaching is true. Without accepting the fact that everything changes, we cannot find perfect composure. We should find perfect existence through imperfect existence. We should find perfection in imperfection. We should find the truth in this world, through our difficulties, through our suffering. This is the basic teaching of Buddhism. Pleasure is not different from difficulty. Good is not different from bad. Bad is good; good is bad. They are two sides of one coin. So to find pleasure in suffering is the only way to accept the truth of transiency.