I stated in my book, in relation to science and objectivity versus prejudiced: If in one's investigations it is expected to find something your convinced is true...you Will find that something.
I suppose the same goes for circumstances in your life as well. For conscious beings, outside of their comfort zones, It's a struggle most of us have; constantly questioning if we have observed justly.

Funny, I just thought of Earl Nightingale's, "strangest secret" : You get or become, what you think about most of the time.

That's why it is important to just observe then strive to prove it wrong.

Polarized thinking is a huge one. I've seen this in medicine, in finance, politics, etc... So many people are so "all-or-nothing" in their thinking. How do they get this way? Just simpletons? Lazy? Lead in the water?

These particular ones might be on the rise. But irrational thinking is the default state for humankind, a state we must rise above.