I went along to an interesting discussion group the other day, on whether "the unexamined life is not worth living." I think the strongest affirmative argument concerns autonomy: if you don't reflect on your life and values, and instead are merely "going through the motions", then there's an important sense in which your life is not even really yours. You're a cog in the machinery of the universe; a mere animal. Experiences happen to you, for better or worse, and may trigger this or that quasi-reflexive "response". But you're not a true agent until you stop and question your own drives and actions, reshape your character into a mould of your own devising, and thereby craft a life that makes sense to you as you live it.
The story of a life is a credit to the author. But an unexamined life has no author. It's a mere force of nature, no more meaningful than a hurricane. So, to live a meaningful life, one must first claim it as their own, and actively author the rest of the story. That's why the unexamined life is not worth living.
But there's probably no such thing as a wholly unexamined life in this sense. Everyone questions themselves, to a greater or lesser degree. So the real question would seem to be: how far should we take this?
Brandon recently pointed out the need for a local/global distinction here. It would be absurd to try to maintain a state of rational self-examination at every local moment. Rather, it is the global exercise of rationality we should endorse, whereby the agent considers the "big picture" of their life as a whole, which will certainly include many local moments at which critical reflection would be wholly inappropriate -- "one thought too many", as Williams put it.
This issue was brought up in our discussion, as one student wondered what to make of a person who, upon reflection, decides that they wish to live an unexamined life henceforth! Would this one moment suffice to establish a considered "global preference", that they spend the rest of their apparently thought-free life acting out? It's a troubling case! I reflectively prefer a life that contains much more actual reflection; but maybe that's just me?
Finally, I was surprised by the assumption of hedonism that drove much of the group's discussion. There are many things I want out of life, and happiness is but one of them (and not necessarily the most important). I'd expect most people to agree. Better to strive for excellence, or help others, than be a blissful couch potato.
So, the challenge to the Socratic mantra doesn't come from blissful passivity, to my mind. Rather, it is the life of non-philosophical activity -- e.g. developing other talents, cultivating loving relationships, and providing for one's family -- that seems the most obvious counterexample. But, in light of the autonomy argument, could such a life still have (intrinsic) value even in the total absense of any self-reflection whatsoever?