Eight thousand Swiss people can't be wrong.
Some might wish they had been, though, according to a study in a science journal.
Researchers in Switzerland found those who viewed their health negatively at the beginning of a 30-year surveillance period proved more likely to fall ill or die during that time span than those who felt the opposite.
Even when researchers took into account risk factors like smoking and medical history the correlation between expectancy and experience remained.
Scientific American reported that men of the same age group who had rated their health as "very poor" were more than three times as likely to die than those who originally rated their health as "excellent". For women "the odds almost doubled".
The Scientific American article concluded, "Maybe optimism also helps keep the doctor away."
Maybe. But optimism versus pessimism isn't an exact formula. Film director Woody Allen is living proof that not all the world's health pessimists pass on at an earlier age. His health outlook is: "I'm not a hypochondriac, I'm an alarmist". But to the relief of his fans he has lived to tell his tales for over three quarters of a century, right up to his Oscar-winning script for Midnight in Paris.
Nevertheless, noting the trend of those Swiss statistics prompts questions. On what basis did those who gave their health a positive rating do so? Why should it have made such a difference?
The research itself doesn't spell that out. But some in the medical profession can offer a helpful perspective.
Best-selling author Bernie Siegel MD, speaking from years of experience as a physician "who has cared for and counseled innumerable people whose mortality has been threatened by illness", says: "The simple truth is that happy people generally don't get sick".
Could that be so? Why should the happy get a bonus for being happy when the unhappy, if anything, need it more? That would seem so unfair.
Except that Dr. Siegel is not referring to the kind of circumstantial happiness dependent on a successful pursuit of pricey pills and possessions or privileged access to particular people and places. He is not even pointing to those more populist "reasons to be cheerful" which punk rocker Ian Dury so poetically articulated.
Dr. Siegel is referring to a happines accessible by anyone, even in trying times, through inner attitude rather than outer events.
And that can come as a relief, given the highs and lows we can sometimes experience when looking for love leads to rocky relationships.
My favourite definition of this more consistent kind of happiness is: "Conscious worth satisfies the hungry heart and nothing else can". The author of those words, Mary Baker Eddy, also said of this spiritual basis for happiness: "It is unselfish; therefore it cannot exist alone, but requires all mankind to share it".
I have come to see the type of conscious worth that encourages unselfishness as revealing more of what we all include - an inherent wholeness. This becomes more apparent as we moderate the sort of stimulation we sometimes tend to pursue, the kind that at best only intermittently delivers the happiness it promises.
That's not to say there isn't room for enjoying life. There's nothing wrong with taking in a Woody Allen movie, being hit with Ian Dury's "rhythm stick", hanging out with friends and family and, of course, falling in love.
But by accepting that the healthiest happiness is what we bring to the table rather than what we hope to take from it we can begin feasting right away and continue as consistently as our resolve permits.
Doing so - I have frequently found - can open one's own eyes to the good one's heart is naturaly yearning for.
Now that is fair.