Are humans too optimistic for their own good?

We humans are a hopeful bunch — so hopeful, in fact, that our views of the future are often irrationally positive. But at what point does unflagging optimism become detrimental to our progress and success? Is there any chance that our starry-eyed tendencies could actually work in our favor, or do they simply leave us… » 4/12/12 8:21am 4/12/12 8:21am