Buddhism.
What it gets wrong. Supernatural stuff - rebirth, karma in the magic sense, prayer. Thinking Buddha's cosmology was ever meant as anything more than an illustrative fable. Renunciation. Equating positive and negative emotions with grasping. Equating the mind with the chatty mind.
What it gets right. Meditation. Karma as consequences. There is no self, consciousness is a brain subsystem, emphasis on the "sub" (Cf. Drescher's "Cartesian Camcorder" and psychology's "system two"). The chatty mind is full of crap and a huge waste of time, unless used correctly. Correct usage includes noticing mostly-subconscious thought loops (Cf. cognitive behavioral therapy). A lot of everyday unreason does stem from grasping, which roughly equates to "magical thinking" or the idea that non-acknowledgment of reality can change it. This includes various vices and dark emotions, including the ones that screw up attempted rationality.
What rationalists should do. Meditate. Notice themselves thinking. Recognize grasping as a mechanism. Look for useful stuff in Buddhism.
Why I can't post. Not enough of an expert. Not able to meditate myself yet.
Not enough of an expert on buddhism, but I live its mother religion - hinduism. There are enough similarities for me to comment on a few of your comments.
Rebirth - The question of which part of your self you choose to identify with is a persistent thing in OB/LW. When X and Y conflict and you choose to align yourself with X instead of Y, WHO OR WHAT has made that decision? One might say, the consensus in the mind or more modern answers. The point is that there are desires and impulses which stem from different levels of personality within you. There are an...
I've often had half-finished LW post ideas and crossed them off for a number of reasons, mostly they were too rough or undeveloped and I didn't feel expert enough. Other people might worry their post would be judged harshly, or feel overwhelmed, or worried about topicality, or they just want some community input before adding it.
So: this is a special sort of open thread. Please post your unfinished ideas and sketches for LW posts here as comments, if you would like constructive critique, assistance and checking from people with more expertise, etc. Just pile them in without worrying too much. Ideas can be as short as a single sentence or as long as a finished post. Both subject and presentation are on topic in replies. Bad ideas should be mined for whatever good can be found in them. Good ideas should be poked with challenges to make them stronger. No being nasty!