I used to have that the-world-is-ending feeling, too. I picked it up by osmosis. Environmentalists were talking like we were going to run out of natural resources any day now (and often predicting disaster just a few years ahead). A lot of people casually mentioned that they expected the world to end any day now from nuclear war, although that might have been exacerbated by the fact that I read books which were written before the Soviet Union broke up. But nuclear tensions have been steadily ebbing, and environmental doomsday predictions have consistently failed to come true, and now I'm feeling optimistic enough to think about actually dealing with a technological future.

By the way, this reminds me of one of the fake job application cover letters from Joey Comeau's book Overqualified, which probably qualifies as a rationality quote in its own right, if only for the brilliant last paragraph. It hails from an alternate universe where Greenpeace isn't stupid and counterproductive.