Dwelling on the irrationality of the part misses the adaptive rationality of the whole

From The Mental Health of Nations by Infovores.  An interesting insight to a Simpson's Paradox in mental health.

Healthy, well-adjusted people successfully make their way through life in part thanks to self-enhancement strategies that accentuate their positive qualities. It is easy to make fun of any one of these enhancements in isolation (recall that nearly all drivers believe they drive better than average), but dwelling on the irrationality of the part misses the adaptive rationality of the whole.

To hint at the connection between positive illusions and national pride just a little more, consider the regard marriage partners have for each other in a thriving and committed relationship. Research suggests that successful couples are still able to see each others faults but look for ways to downplay them while looking for silver linings and emphasizing more positive qualities. What some might call cognitive distortions probably enable them to stay together.

Critics of irrational behavior are, sometimes, merely fixated on the wrong lens.  What can be tactically irrational might be strategically rational.  It is like winning battles and wars.  Ideally, you win all your battles AND win the war.  But that's not the real world.  Sometimes, you win all the battles and lose the war.  It is also true that you can lose some or most of your battles and win the war.  

Similarly with adaptive rationality.  Some behaviors are tactically irrational but are strategically markedly effective.