“Because he tells you “I’m gonna search your car”.”
Well then he’s not really asking is he? You can still say “I don’t give consent to a search”, but you’re not going to stop him. Give him grief and he’ll just lie and say you did give permission.
However my own real life experience of dozens of interactions with cops from traffic stops to being arrested (I forgot a court date for a traffic ticket), I’ve only encountered one cop who was a a-hole. He followed me for about 2 miles of city traffic looking to pull me over, then ticketed me for making an “illegal turn” that was legal. One good thing that came from that was a traffic school class taught by an ex CHP. The class was basically how to avoid getting a ticket. One thing he stressed was not to argue with the cop on the scene, take your ticket and go to court. First, the cop may not show up, and you win. He probably won’t remember you, and won’t have notes if he does. If you argue, he will remember you, make copious notes, and possibly lie about it. In short he will be out to get you. That’s common sense in the real world.
I've never encountered an A-hole cop. One Compton PD officer who was mildly harsh, and after I put the sticker on my plate he let me go without so much as a citation.
And yes, I've had scores of interactions.