Pessimism:

"The last evolutionary epoche was the ice ages and the mentality that said 'It's a lovely day in Philadelphia today. It probably be a lovely day tomorrow." got crushed by the ice.  And the mentality that was catastrophizing 'Looks like a lovely day in Philadelphia today. But this is just superficial. And what's really coming a catastrophe.' is what our intellectual evolutionary forbearers, the ones that survived, gave us. So we are bad-weather animals. Ready to see the most catastrophic. Now, that's very adaptative if you are in Bosnia during the war. Or if you're living in a society in which there is death and famine and plague."

Martin Seligman