Imagine this Scenario,

There is three bucket in front of you. First one contains hot water, second one contains cold water and last one contains water having room temperature. You have to dip your right hand into hot water and left hand in cold water for one minute. Then put both water into third bucket having room temperature water.

What would be the result ? Room temperature water will feel cool in your right hand and hot in your left hand.

This is the flaw in our mind.

Our mind makes judgement of something being beautiful, expensive, large or reasonable if we have something nasty, cheap, small or unreasonable in front of us. Our mind have great difficulty having “Resolute Judgement”.

“We value things depends on what we compare them with”.

There is popular notion in the society about Age of marriage. You are suppose to get married between 26-30.
What would be their mediocre argument behind it?
Because your 24-25 year old colleagues or siblings or friends are getting marry.
At the same time, there are people who are getting married after 30 too.
But the average mind is clouded with Contrast Thinking, It just entertain itself with popular notion it found in society.

Another Example I have personally observed in Business world is New iPhone line up launching.

The price of some iPhone models looks reasonable because what we compare it with.
iPhone 11, iPhone 12 and iPhone SE drives our decisions because there is iPhone 11 Pro, iPhone 12 Pro are right beside it. Price of those flagship models influence our decisions. Flagship models justifies the price we pay for their base models.

In fact the data suggest that iPhone 11 was the best selling iPhone this year. Why?

There is contrast bias played its role on large scale.

In my generation, when women lived at home until they got married, I saw some perfectly terrible marriages made by highly desirable women because they lived in terrible homes. And I’ve seen some terrible second marriages which were made because they were slight improvements over an even worse first marriage.
-Charlie Munger.