Worry

Near the end of his life, Mark Twain said: "I am an old man and have known a great many troubles, but most of them never happened.” How many hundreds of hours have we spent agonizing over possible problems that never actually happened?

Ralph Waldo Emerson said it more poetically:

"Some of your hurts you have cured,

And the sharpest you still have survived,

But what torments of grief you endured