Without daytime, a night lit up by moonlight would not be as beautiful.
Without gloomy and rainy days, we would only complain about the sun's heat, not appreciate it for casting the cold away.
Without the pain of loss, it would be easy for us to take everything for granted, and cherish nothing.
Contrast brings beauty to life. The bad brings beauty to the good. The good makes the bad not so bad.
As such, there is beauty in everything. Even the worst things.