Something that has always bothered me, is that normally intelligent individuals with common sense will just stop thinking on certain subjects and simply follow their chosen party line. Which party line doesn't matter, the fact is, they gave up thinking for themselves, and replaced someone else's conclusions with their own process of thinking.
This often happens with political or religious thinking, but it isn't limited to that. It can be with something as simple as following sports, fashion, etc.
A person acting in their highest capacity thinks for themselves. Following the herd, or simply taking someone else's judgment can be wise (and even necessary)in certain situations, but for the most part, it is how one can get constantly manipulated their whole life.
That is not to say that one should become an expert in every subject. This is impossible. When bringing you malfunctioning car to an auto mechanic, you pay for the mechanic's expertise. However, giving up on learning the basics of how a car works, and thus having no idea as to what might be wrong, allows you to be manipulated by said car mechanic.
At an early age, we are forced to accept the authority of others to survive. Your parents or guardian, while growing up, seem to know everything about the world and it behooves you to accept their opinion on just about everything. At some point, most people wean themselves of their parent's authority, but then place their deference to authority in other persons or groups (government, politician, teachers, religious books).
This thought process is reinforced in schools. The teacher is the authority figure that has all the answers. Thinking for yourself, and differentiating from the teacher is punished. Being correct, is not a sufficient justification for being different. In my own experience, this continues at least through undergraduate school. Some professors and teachers that are exceptions to this rule, but they are the outliers.
Perhaps, much of this thought process is genetic or came to us as a survival skill, and I am exaggerating the nurture factors that contribute to this "follow the leader and damn the thinking" mentality.
What I find humorous, is that many people see this quite clearly in others, and condemn it, but do not accept that they do this themselves. I've seen many die hard atheists, that come to their conclusions by blindly following scientists, professors or other authoritative figures that they trust, while mocking a religious fundamentalist for blindly following their leader. That is not to say that the atheist or religious fundamentalist is necessarily wrong in their belief, (both of these are almost by definition impossible to prove), but they would be deny that they used the same fallacious logic to get to their opposite conclusions.
This same type of thinking is all too prevalent in almost all political discussions. Once my "side" is right, your "side" is wrong. No further thought process is needed. My "side" whether it be pro-Michael Moore, George Bush, abortion, war, etc. has already been chosen by me. I've decided my team, tribe, authority, whatever you want to call it. All that's left for me to do is decide why you're wrong. Usually, even this answer has been chosen by my authority . The deliberation is left out of the argument.
It's time for us as human beings, if it's possible, to go beyond this neo-tribalism. We can, and should, be better than this. But before this is possible, we must accept that we are susceptible to such thinking.