Our Gemara tells us that how Haman reacted when Ahasuerus ordered him to fulfill his idea of the proper way to honor one who the king desires to glorify by parading him around on the king’s horse while wearing the royal garments: “And do so to Mordecai the Jew who sits at the king’s gate, let nothing fail of all that you have spoken” (Esther 6:10). The Gemara explains that when Ahasuerus said to Haman: “And do so to Mordecai,” Haman said to him: Who is Mordecai? Ahasuerus said to him: “The Jew.” Haman then said to him: There are several men named Mordecai among the Jews. Ahasuerus then said to him: I refer to the one “who sits at the king’s gate.”

This is stage one of Haman’s process. When he can no longer deny that indeed, Achashveirosh is referring to his nemesis, Mordechai, he starts to bargain:

⁦Haman said to him: Why award him such a great honor? It would certainly be enough for him to receive one village [disekarta] as an estate, or one river for the levy of taxes. Ahasuerus said to him: This too you must give him. “Let nothing fail of all that you have spoken,” i.e., provide him with all that you proposed and spoke about in addition to what I had said.

We are observing various defenses within Haman’s process that are object lessons.  The most prominent that we see is what is called “Confirmation Bias”.  Confirmation Bias is about how people select data, to confirm what they already think is true, as well as what they wish or need to be true.  Some of the processes of confirmation bias involve:

• Attitude Polarization (when a disagreement becomes more extreme even though the different parties are exposed to the same evidence).  Easy examples of this can be found in politics and religion.
• Belief Perseverance (when beliefs persist after the evidence for them is shown to be false) 
• Irrational Primacy Effect.  That is when you give more weight to the first opinion, just because it came first.  The Rambam mentions this complaint in his introduction to the Sefer Hamitzvos.  He says that people tend to stick with the first opinion they hear, and that is why they cling to the Bahag’s enumeration of mitzvos even though they were meant more poetically than rationally. 
• Illusory Correlation.  This is when people look to see correlation that is not there. Just think of the debates people have regarding COVID.
• Selective Recall. Because memory is fallible, associative and interpretive, we will naturally remember events that correspond with our beliefs and conveniently forget those that do not.  Even if that happens a small percentage of the time, that is enough to tip the scales of denial.  “Hmmm.  I wasn’t really that abusive when I lost my temper…”

The main danger of Confirmation Bias is that the truth is lost.  Life offers so many conflicting sources of data that we will inevitably pick and choose.  The problem is that we will tend to minimize data that makes us uncomfortable and forces us to change our assumptions, status quo or see ourselves in a less than complimentary manner.  Yet we will also add greater weight to data that justifies ourselves.

The havoc that this wreaks in relationships is that we justify our behavior instead of listening.  Yet, the gift of relationships with children and your spouse is a chance to be challenged and confront new information.  The people who are the biggest source of conflict and frustration for us can also be the greatest source of new data and information.  Precisely because they have different values, perspectives and assumptions, even if, mind you they are incorrect, naturally their confirmation biases will be different.  They might take in data that your own filter will not allow through, and vice versa.

Source:

https://en.wikipedia.org/wiki/Confirmation_bias