As part of my role, I make first contact with people who have called in to make a complaint about police. I am expected to establish what the complaint is, and try and deal with it before formally recording it. Some are not actually complaints, just a misunderstanding by the person who took the initial call. A number are made by people who believe they can avoid criminal prosecution by making allegations against the officer who dealt with them. Some are genuine, and these are recorded and submitted for further investigation.
Another group are those people who have a total inability to accept the views or opinions of others. Such people can never accept that they may have been in the wrong, and will argue against the most compelling of evidence. Such people spend their lives in battle with various authorities, neighbours and anyone else who challenges them. They are an expert in every field.
I find such people fascinating. Something within them causes them to genuinely believe they are in the right - any argument to the contrary is rebuffed, and police, courts and witnesses are all accused of error. It is not that these people are lying, they really do believe their own account of events. It is as though their brain has some kind of defensive mechanism that prevents feelings of being guilty or wrong. They are totally unable to empathise or see things for the point of view of others.
One of my officers is like this. She is one of the worst performing officers I have ever experienced, and has taken a significant portion of her career off sick. All challenges to her are rebuffed - she genuinely believes herself to be very good at her job, despite the lack of any evidence to that effect. All efforts to help her improve are met with contradictory arguments and allegations of bullying. She cannot accept that she is bad at her job, and believes that her needs must always come first. Unfortunately, it is incredibly hard to be sacked from the police for poor performance. She will see her career out in some pointless office job, making constant allegations requiring investigation to be found to be baseless. Much as the deluded members of the public who insist on making complaints to cover for their own failures. They all take up valuable time and tax payers money that could be better used elsewhere.