Dilbert guy Scott Adams wrote a few weeks ago about his biggest worries.  On his list were a bunch of relatively small things compared to the grand scheme of the world and what everybody else worries about.  His rationale is this: 

"First, I'm not worried about any problem that we can see coming.  If you look at the history of the world, almost any time we thought we knew something bad was going to happen AND we had years of warning, things turned out okay."

I think that's a great way to look at things.  Global warming will cause World War 3, the world's petroleum supply will run out, and we'll be forced to compete with illegal aliens to generate electricity by running in giant hamster wheels.  But eh, somebody will figure something out.  What can I possibly do to affect any of it?  Nothing.  Except keep my legs strong.