Sigmund Freud thought "ordinary unhappiness" was the human lot. He went on to write that what makes us even more miserable is a neurotic scheme to rescue ourselves from what can't be helped.
Take Shakespeare's Macbeth. He was ordinarily unhappy; he had divided loyalties between his wife and his king. Well, we all have those -- it's part of our usual sadness in life. But instead of living with these divisions and managing them the best he could, Macbeth happened upon a radical solution: he'd just kill the king. This made him even more unhappy -- tragically so, in fact. He should have read his Freud. Willie Nelson had read his, as when he sang:
Why do I have to choose
And everybody lose?
Everybody sing the blues.
Well, darling, I refuse.
It's too bad that Willie was a much better Freudian than Macbeth was.