Police are just humans, they have their biases and grudges and bad days like everyone else. But the power they hold means those bad behaviors can harm you quite a bit, in the same way it can help you when you need it.

Exactly, and that's why you need to invest in training and guiding them, in holding them accountable for missteps and bad behaviour.

The point of police is not to give untrained regular people unchecked power over others.

Your vague broad-scale social prescriptions are irrelevant to the question of optimal individual behaviour towards the police.

No, but they are relevant to the question of how to improve your society. Accepting problems as a normal state of affairs is not going to fix them.

What I wrote is valid for the most well trained police force in the world.

It should be a massive condemnation of our laws, which they just try to uphold.