[mmooss]

> Surely you can imagine a situation (or many) where thinking more positively about a situation than the data warrants leads to bad outcomes?

We're not talking about hypotheticals - we can always construct hypotheticals that yield the answer we desire - but the real world.

[pluralmonad]

None of your examples above tie directly to an optimistic disposition. How could you possibly know the disposition of the thousands of humans involved in those endeavors? You are letting your personal disposition color your view of the world (as we all do) and mistaking this for some sort of absolute truth.