Perspective
I used to feel that battling and learning how to overcome cases of cognitive dissonance was a worthy cause; I wanted to show and teach people that there are more than one way to do things. This itself was egoic behaviour; a case of low self esteem attempting to empower itself by seeing it win someone over to its current paradigm. I have since realized that this in itself is a waste of time.
Cognitive Dissonance itself is a cause of the law of polarity; Everything has its opposite, one view will contradict another when beliefs are challenged; depending on how strong the beliefs are can influence the outcome. It is rarer that cognitive dissonance occurs with open and cleansed minds.
There is a saying where I am from that goes
"You can lead a horse to the trough but you can't force it to drink".
You can talk all you want about your opinion and attempt to demonstrate it but if the other person is unwilling to take a sip from your opinion cup then it will fall unheard at best or even turn heated.
What can be done
I gleam knowledge from the following passages in the bible under Matthew 7:
You hypocrite! First take the beam out of your own eye, and then you will see clearly to remove the speck from your brothers eye. Do not give dogs what is sacred; do not throw your pearls to pigs. If you do they may trample them under their feet, and turn and tear you to pieces. Ask and it will be given to you; seek and you will find; knock and the door will be opened to you.
This talks of coming to the situation with a distinct awareness and being open before attempting to understand anothers perspective. The dog and pig symbolize the animal carnal mind that we can overcome with practice; the sacred represents the words and vibration spoken and felt. Only when someone is willing to receive knowledge will it be presented to them; by seeking, they open a space to make this objective come to fruition.
In conclusion
By engaging with someone who is suffering with cognitive dissonance you will be actively giving their issue your own energy and time. If time is money and energy is life then you are doing a great deal of injustice to yourself and those around you. You can show someone the door but they have to be willing to engage and walk through themselves for them to be open to receive any true meaning from it.