My oddball reply:
An interesting poll, but actually happy/sad are not states I relate to. Though I may use those words in communicating with others as they are part of a common language.
Do I feel? One might ask. Yes, deeply. Passionately. About almost everything. But my feelings do not rule me.
Is there great pain in existence? Of course. But there is a way to accept what is unavoidable and move on, without losing our capacity to function. And if we do lose it, one is not to be blamed. But should seek help, for there is help to be had. Though sometimes hard to find.
I think if I operated on a happy/sad yardstick, I would have found it difficult to go on with life a long time ago. And I have deep compassion for people that also operate outside this range, but don't realize it, and are always measuring themselves or their lives thus, and thinking they are lacking.
For me, it is all about having a sense of purpose in how I exist spiritually. Is the best I can describe it. I may laugh, I may cry, but these are transient moments and I know it. I have successes, I have failures. They shape my earthly life, but do not define me.
Joy and sorrow walk hand in hand in my, I admit, very turbulent world, and I cannot separate them out to measure them. I accept them, but my focus is elsewhere.