Depression is called a disease, but not happiness.
Genuine sadness and depression are better than fake happiness.
Sadness may be a symptom of healing from the disease of false happiness. It may be a step in the right direction, closer to truth and reality. We ARE reality, and yet as far as conscious experience goes, we may live in a fantasy world created by the mind that is mistaken for reality.
Who hasn't suffered from the disease of fake happiness? There's a massive epidemic, the whole world is mesmerized by the pursuit of fake happiness, the happiness found through the ego gratification of success, recognition, relationships, acquisitions, etc.
The spiritual awakening happening individually and collectively today is not immune from this error. Spirituality can be fake happiness. I've used (mis-used) spiritual truth myself that way many times, and still fall into this trap. "I am awareness" can become another story used to pretend that I don't feel the sadness and confusion roiling around inside.
All I can do is notice the bigness of not-knowing that surrounds my small story-of-knowing.
Reality is just so real! I know that sounds dumb- but there is this zoom lens that is closer than any cognition- there is this dynamite of non-verbal reality- uncategorized, un-thought, un-tampered with- so abundant and unavoidable- that is equally present in sadness and happiness.
The more I allow the genuine sadness and fake happiness and all the rest to do its dance- the more this Reality reverberates in infinite openness.