As someone who has been through the criminal justice system a handful of times, here's what I always tell people: If you are approached by a policeman/woman, you don't need to say anything other than, "I'm going to ask you to refer all questions to my counsel as I'm not prepared to handle or able to answer any questions you may have." Don't have counsel? Get some. Can't afford any? Tell the policeman/woman that you'l…
It seems to me that this advice forgets it's own lesson: A policeman/woman can only get you in trouble. In many cases, a copy really does just want to have a 5 minute chat, and if you stonewall them ( Am I being detained? ), they might decide to exercise their power to get you in trouble, just to return the sentiment of unreasonableness.
Police culture and training promotes this toxic type of no-common sense approach to handling situations, it trains them to be assertive and the 'alpha-male' in all situations, so any type of rebellion against this idea to them is treated as sacrosanct, at least by the average (aka dumb) officer.
And yes, for the most part if you are respectful and non-confrontational you won't have any problems.
Some people reject this entirely and think they have rights so they should assert them always. But ultimately these are social situations in which one party is given a significant imbalance of power, that goes well beyond the rational/common-sense "I didnt do anything wrong" context, and which goes well beyond the rights you do actually have - in a courtroom in front a judge.
The simple fact is police can make your life miserable without crossing any legal/employer boundaries. The bureaucracy, political culture, and power structures allow this to happen.
So if you care about this try to focus your energy on changing politics, police training, and the accepted police culture at the society/community level. In individual moments it's probably not worth the energy.
But that said, never ever say anything you don't want to reveal to a police officer, even (or especially) if you broke a law, and never trust a single thing they say about it being "the best thing for you to do at this moment". Be polite and listen to what they say in terms of behaviours, but if you are pressed repeatedly after not wanting to say something, then say you want a lawyer present because you don't feel comfortable in this situation. And yes sometimes that requires you being a "dick" to be assertive, but that's because the police have an incentive to make you feel that way. As long as you are a good citizen otherwise they have nothing on you and the truth will come out in court, if they can prove you did anything to get to that point.