I'm Tuvia Dulin, and I ended up on these forums after reading Harry Potter fanfiction. I suspect that this is a common story among the membership.
I've tried to be rational ever since I learned what rationality was, but it wasn't until I suffered a psychotic episode that I learned what the true consequences of irrationality were. That was many years ago, and I have since completely recovered, but in some ways I'm glad for the experience; it taught me that without rationality, you have nothing dependable or sane.
"Rationality" is defined a bit differently here than in other places. There is good justification for this. It makes me suspicious any time I hear someone discuss the meaning of a word, as it makes it likely they are invalidly trying to argue by definition, but here "rationality" has a close meaning within and without LW, closer than any other word, and also sufficiently close that it is better to use it than use a new word.