The concern is that it may not ever be better enough for me to register a sense of approval or contentedness.
Contentedness is based on the interaction of your desires and your outcomes. You are becoming more realistic about your outcomes (this includes 'expected outcomes' here because we are predictors and count the future as part of the present). What is the natural next step?
The future is an uncertain, scary place. That means normality is a win. Every day you and the people you love survive without injury is a win. Every day you sit down and improve something instead of letting time slip through your fingers is a win. You understand that normality is more tenuous than you thought it was before; complete the circle and understand that normality is more precious than you thought it was before.
If you feel failure is more likely now that you anticipate the future more clearly, then develop a love of failure, for it is the parent of success.
You seem to be arguing that I should lower my sense of which outcomes are "good enough" so as to match the outcomes that are likely to happen, but I'm not convinced. My sense of what is good enough is deeply entangled with my emotions and my moral intuitions -- even if I could artificially lower it, the side effects would probably do more harm than just allowing myself to be scared or upset about the likelihood of not-good-enough outcomes.
Recently, I've been ratcheting up my probability estimate of some of Less Wrong's core doctrines (shut up and multiply, beliefs require evidence, brains are not a reliable guide as to whether brains are malfunctioning, the Universe has no fail-safe mechanisms) from "Hmm, this is an intriguing idea" to somewhere in the neighborhood of "This is most likely correct."
This leaves me confused and concerned and afraid. There are two things in particular that are bothering me. On the one hand, I feel obligated to try much harder to identify my real goals and then to do what it takes to actually achieve them -- I have much less faith that just being a nice, thoughtful, hard-working person will result in me having a pleasant life, let alone in me fulfilling anything like my full potential to help others and/or produce great art. On the other hand, I feel a deep sense of pessimism -- I have much less faith that even making an intense, rational effort to succeed will make much of a difference. Rationality has stripped me of some of my traditional sources of confidence that everything will work out OK, but it hasn't provided any new ones -- there is no formula that I can recite to myself to say "Well, as long as I do this, then everything will be fine." Most likely, it won't be fine; but it isn't hopeless, either; possibly there's something I can do to help, and if so I really want to find it. This is frustrating.
This isn't to say that I want to back away from rationalism -- it's not as if pretending to be dumb will help. To whatever extent I become more rational and thus more successful, that's better than nothing. The concern is that it may not ever be better enough for me to register a sense of approval or contentedness. Civilization might collapse; I might get hit by a bus; or I might just claw through some of my biases but not others, make poor choices, and fail to accomplish much of anything.
Has anyone else had experience with a similar type of fear? Does anyone have suggestions as to an appropriate response?