I highly recommend "The Underachiever's Manifesto: The Guide to Accomplishing Little and Feeling Great": http://www.amazon.com/The-Underachievers-Manifesto-Accomplis...

Face it, if we're reading HN on a Saturday, probably thinking about work, we're probably saddled with the nagging feeling that we're not achieving enough. But achievement can become a dangerous addiction that makes us unhappy.

There are common themes in the book that come up in software engineering as well, like "perfect is the enemy of the good" and "the law of diminishing returns applies everywhere". It's a rational way to think about living.