No evidence and arguments help - such a person hears only himself. They do not lead a normal adult dialogue, they will interrupt, caulk your mouth and just interrupt the conversation if they disagree with something. Strangely enough, the reason for this stubbornness may be insecurity, but you are not a personal psychotherapist of this person to deal with his childish or not very childish traumas. Your job is just to save yourself and your nerves.
These people do not know how to maintain a normal dialogue. They are so absorbed in themselves that they are sure: everyone should listen only to them, so they say without stopping and interrupt on every word.
it's part of the "positive" thinking. they are trying to save you ...
I am sure that all the positive good vibrations from the 1960's and since then have had such a dramatic and effective impact on the world. Why just look around you everyone has food - be happy - no violence in the streets - be happy - No world wars - be happy - .
Yes good intentions positive thoughts karmic giveaways, they have all had such a wonderful effect on the world as we know it.
We may as well be whistling in the wind as train with it's horn blaring passes by. They will not hear.