Patriotism, nationalism, religious orthodoxy, unquestioning adherence to cultural traditions - these are all poisonous human values. They breed group righteousness, intolerance, contempt, hatred, and war. While leaders may be motivated to war by greed, the populace is motivated to war by fear and hatred of the other.
On the surface, most people would without hesitation condemn the quality of self-righteousness, considering it to be a dangerous human character flaw. Unfortunately, those who believe they are right, truly believe that they are right, and therefore usually feel that it is acceptable for themselves to believe that they are right - a strange logic trap and lapse in reason, indeed.
Group righteousness - where one group considers itself and its members to be more righteous than some other group - is a poisonous human value. And this applies just as well to liberals feeling that their group is more righteous than conservatives, and conservaties feeling that they are more righteous than liberals. Integration and the cross-pollination and interchange of ideas, values, and traditions are what we need in order to establish a lasting peace. Uncritical adherence must be overtaken by ecclecticism, pragmatism, and the malleability and adaptibility of people's beliefs.
Even the quality of being principled frightens me, for it is a fine line between being principled and being dogmatic and intolerant. Certainly there are times when being principled seems like a good thing, provided the principles in question are healthy and constructive. But the danger of being principled in a destructive way seems to me to outweigh the occasional benefit of people being constructively principled. Pragmatism, it seems to me, more likely has a positive net value to humanity than principledness.
One might liken the more fluid pragmatic approach to the mechanism of sexual reproduction in species, and the more rigid principled approach to the mechanism of asexual reproduction. While asexual reproduction produces clones and guarantees the propagation of strong genetic qualities, it also guarantees the propagation of weak genetic qualities and precludes the adaptive emergence of new qualities that may be better suited to survival in a changing environment. Religious fundamentalism is an extreme example of the aseuxual reproduction, so to speak, of ideas and cultural values. On the other hand, a more permissive secular society would be an example of the sexual reproduction, so to speak, of ideas and values.
Time has proven the sexual approach to reproduction to be more resilient to an environment with an ever changing climate and geology. But, to speak to my earlier point, the answer often really lies inbetween two extremes. So, it may in fact turn out that what would serve humanity most effectively, would be a balance between the stability that is provided by a healthy level of adherence to previously established values, and the adaptibility and potential to grow that is provided by a healthy level of questioning and re-assessment of previously established values.
The biggest mistake may, indeed, be the vehement belief that one extreme or the other is correct. Indeed, there are examples in nature of species that go through generational sequences of sexual and asexual reproduction, perhaps resulting in a best-of-both-worlds situation, or at least a particular blend of the two approaches that has come to serve the species well.
Certainly, a belief that nothing is sacred is essential. Everything is fair game for critical analysis. As a species, we must find the healthiest balance between the cloning and hybridizing of ideas.