I've made it to Ecclesiastes in my scripture study (finally) and I LOVE this book. The irony is, the "Preacher" knows what I just learned. Ecclesiastes 7:3
Sorrow is better than laughter; for by the sadness of the countenance the heart is made better.
I don't think he's saying that sadness is really better, but that sadness is necessary, and better than false happiness.
It's catharsis. Sadness and pain and fear are necessary. They're healing. If we experience them, it's like eating the food before it gets moldy and stinky and festering. Otherwise, it just gets stuck in the fridge and no one wants to clean it out, because even though it's no longer edible, it reeks. It creates stink everywhere. It contaminates everything.