Couple of years ago in outback Norway a truck driver didn't like my, completely-safe-deserted-road-and-clear-for-about-half-a-mile-in-each-direction, overtake. He flashed as I passed then radioed local Police who pulled us a few miles down the road. They eyeballed the car, moaned about the rental company's summer tyres in April, asked us about overtaking, had a quick chat about our road trip and let us go with the advice that winter tyres are better for the arctic circle. The next day I found out he was correct, nearly pooed my pants in a blizzard on a mountain.
Most polite interaction with police ever.