Several people have already e-mailed me today with their Death Clock projected date of death. Note that the "mode" feature is not, as far as I can tell, whether you are "optimistic" or "pessimistic" in life, but whether you want an optimistic or pessimistic (or, "sadistic") prediction. While it is assuredly true that optimists may have health advantages over pessimists*, the difference isn't this large.
To give you an idea of the differences, here are my own projections keeping all information the same:
"Normal": Christmas Day, 2043 (age 72)
"Pessimistic": November 2, 2026 (age 55)
"Optimistic": January 14, 2063 (age 91)
"Sadistic": Christmas Day, 2007 (age 36--great! just in time for tenure!)
* An academic BTW: I heard a talk last year where a personality psychologist claimed that pre-test measures of personality and optimism explained 30-50% of the variation in pre-test-to-post-test change in self-reported health for a sample of patients. The implication was not that most of this difference was due to actually-better-health, but rather it was due to reportedly-better-health--that is, pessimists, being pessimists, are more likely to the glass as half-sick while optimists see it as half-well.