Very good point!
Both my husband and I have cognitive challenges (don't we all, we imperfect results of evolution, us) that constantly threaten to sour our relationship. We strongly credit our study of cognitive science and rationality for keeping our relationship sane and enjoyable. We make conscious decisions about how we manage our moods relative to each other. We work hard to recognize cognitive biases and to tease out objective fact from fallacy. We have a very strong, twenty year relationship because of that.
Then again, one of the things that attracted each of us to each other was the fact that we were both rationality-seeking and valued that in the other. I believe, however, I can make a rational case that our approach towards mutual anger management, anxiety management, and so on, has helped our relationship to remain strong, fruitful, and enjoyable.
For certain, understanding the philosophy of science -- minimally, the concept of "confounding variables", along with other concepts and practices -- has helped us get and keep my husband's bipolar in control. For about a year he was hallucinating due to some medication imbalances. His understanding of experimental methods and rational thinking helped him differentiate hallucination from reality during that period. Our understanding of science has also helped us make some pretty good decisions about our health, and even about our dog's health (the little tyke is 17).
I want to master x-rationality because I want to teach it. I value rational behavior in my fellow human because the historical record is clear: rational behavior is correlated with increased safety, health, and wealth of a society. I want to live in an increasingly safe, healthy, and wealthy society. I understand that "rational" behavior has a saturating plateau, or that it is only so effective, but the masters of rationality must continue to exist in every society, scientific skeptics must be cultivated. I enjoy working with the rational arts because, frankly, I grew up with a very irrational mother and I have lived ever since to do everything in my power (of almost a half a century now) to be everything she was (and still is) NOT. I want to be one of the rationality masters and teachers in my society because I enjoy those arts, find value in them, and find value in safety, health, and wealth.
Pretty selfish, but there it is.
It can be rational to accept the responsibility of high risk/high reward behavior, on specific occasions and under specific circumstances. The trick is recognizing those occasions and circumstances and also recognizing when your mind is fooling you into believing "THIS TIME IS DIFFERENT".
A rational agent is Warren Buffet. An irrational agent is Ralph Cramden. Both accept high risk/high reward situations. One is rational about that responsibility. The other is not.
Also, in a world of both rational and irrational agents, in a world where the rational agent must depend upon the irrational, it is sometimes rational to think irrationally!