And yes; sadness is as well a need.
We cannot laugh the whole life, we cannot be happy until we die. Because life matters when we could value all the meanings that happen. We would never learn something from only goods.
The obstacle we face is the struggle that makes us strong
Cliche it is. But nobody proved it is not right.
I am always a devotee of sorrows. Because it makes me more sensitive. It makes me think more than anybody who always gets anything easier. It makes me find solutions. It makes me appreciate more. And the most important one is that it makes me a sincere one, oh Amor Fati.
So, being sad is not wrong at all. At least you don’t forget to have fun. Be balanced :)