I used to be, and still am to a large extent, a pessimist. Over the years pessimism affected my worldview and guided my actions. In the past few years though, I've changed quite a bit toward optimism. But it was not until recently I start to reflect on those changes, absorb alternative opinions, and philosophize on the nuances of being pessimistic about different things.
Like many people frustrated by how history repeats itself again and again, I also believed that humanity is doomed. There are simply too many challenges to solve while we can't help hurting each other. My mind started to change after I listened to Naval's podcast about The Beginning of Infinity (book by David Deutsch). One main theme is that knowledge is infinite, humans are unique in our capability to understand things, and how pessimism is an easy trap to fall into when considering where the future of humanity holds:
If you could predict it, you would have invented it already. A lot of our deeply pessimistic world views come from a straight-line linear extrapolation of negative trends while ignoring positive trends. Positive trends mostly come through creativity and knowledge creation, and it's inherently unpredictable.
On another front, I'm what some rightfully call a productivity geek. I use everything from Getting Things Done systems to Time Management techniques to work toward achieving personal goals. Because I fear that I won't be able to succeed otherwise, as anything could go wrong. The other day I read The Imperfectionist: It's worse than you think, which made me think that maybe I'm not pessimistic enough:
... you feel overwhelmed by an extremely long to-do list. But it's worse than you think! You think the problem is that you have a huge number of tasks to complete, and insufficient time, and that your only hope is to summon unprecedented reserves of self-discipline, manage your time incredibly well, and somehow power through. Whereas in fact the incoming supply of possible tasks is effectively infinite (and, indeed, your efforts to get through them actually generate more things to do). Getting on top of it all seems like it would be really hard. But it isn't. It's impossible.
Perhaps it's time to rethink long and hard.