You clearly never seen police dashcam videos in the US. Besides the corruption and stops for "hunt missions", a lot of times it's simply because you shattered their ego, even with a simple laugh: https://youtube.com/watch?v=NqJdt9_1XSw
This is also why mobile phone camera tech led to BLM as more and more people became aware of how police act when they think nobody is watching.
https://www.youtube.com/watch?v=isYZoFrIeo0
However, the poor guy only defeated criminal charges on appeal!