We're all human beans

...and human motivation is a fascinating subject. To me at least.
Anyway, here's an interesting theory about the topic from a post-apocalypse sci-fi novel called A Day For Damnation by David Gerrold.:

[You have] only two responses... Yipe and Goody. There aren't any others. Everything is variations on that. There isn't an animal on this planet that doesn't have that basic mechanism hard-wired into its cerebral cortex. That's your machinery. You can't not react with yipe or goody. And most of the time, just to be on the safe side, you react with yipe. So you spend ninety-nine percent of your life running your yipe machine...

I think the above may be overstated a bit, but I do believe that:
a) we tend to err on the side of fear (yipe) when experiencing new things, and
b) we're naturally predisposed to put things into one category or the other. Dividing the world into right/wrong, good/bad, black/white (ie, knowing whether something is a yipe or a goody) makes us feel more in control, less fearful.

It seems like we might all be happier if we learned to react more often with "Hmm" or "Wow" or "I wonder"...