When faced with impending death, pessimists might commit suicide. Optimists might struggle on. People with under-developed personalities might just listen to the first person they run into.
But whatever the case, their choices will be broadcast through their religious and cultural values. Those committing suicide could self-terminate. Or they could be suicide bombers. Those deciding to carry on could become artists or prophets. Or they might open a house of worship.
In addition, the definition of "impending doom" changes depending on your philosophy of life and worldview.
It's a red herring to blame everything on religion. People are people. But it's also a red herring to refuse to accept the role of religion in determining how well cultures thrive. Whatever myths you choose to believe in has a profound impact on how you see the world around you and how you react to it.