But the undodgeable reality of a finite human life is that you are going to have to choose. - Oliver Burkeman

A person who has resolved to 'think positive' must constantly scan his or her mind for negative thoughts – there's no other way that the mind could ever gauge its success at the operation – yet that scanning will draw attention to the presence of negative thoughts.

John Maynard Keynes saw the truth at the bottom of all this, which is that our fixation on what he called "purposiveness" — on using time well for future purposes, or on "personal productivity," he might have said, had he been writing today — is ultimately motivated by the desire not to die. "The 'purposive' man," Keynes wrote, "is always trying to secure a spurious and delusive immortality for his actions by pushing his interests in them forward into time. He does not love his cat, but his cat's kittens; nor in truth the kittens, but only the kittens' kittens, and so on forward forever to the end of cat-dom.

Once you no longer need to convince yourself that the world isn't filled with uncertainty and tragedy, you're free to focus on doing what you can to help. And once you no longer need to convince yourself that you'll do everything that needs doing, you're free to focus on doing a few things that count.