There is a concept in business and many other arenas. One does not need to recognize the bad to be able to recognize and appreciate the good. They study the good. The simplest example is the Secret Service agents who work with counterfeit currency do not study the counterfeit examples. The study the legit examples. They know what the good stuff looks and feels like so the bad stuff is obvious.

We don't need to experience sorrow to recognize joy. For those of us who struggle with a flat affect, we may struggle to experience joy but often the last thing we need is to experience deep sorrow. We often live on the edge of sorrow most of the time.