Pretty similar to my experience in the US.

Generally, a 15km/h speeding won’t even get you stopped. Once I got pulled over ostensibly for about that much over, but it was 2 in the morning on a weekend on a country road so I’m pretty sure the officer was just using the speed as a fishing expedition, and came up with nothing worth the paperwork over.

Another time got pulled over for ostensibly speeding, and when the officer asked if we knew how fast we were going, I started tapping on the screen to try to pull up what would have been dashcam footage, and the officer fairly quickly decided to leave us with a “you just be careful now”.

Like you said, at no point did I get particularly pissy, on the first I was a teenager who had never been pulled before and was just being super deferential, and even with the dashcam I was genuinely checking if I had such a thing because it was a new car and I wondered if I could access the camera recording (I heard that in a crash it would have recorded something, but evidently without activating or crashing it, it wasn’t there). But never said that I doubted him, just that I was going to see if I could see how fast I was going.

If the whole scenario is low stakes and the officer is not stressed, my experience has been like yours. Only time I personally witnessed a pissed off cop was when I got rear ended by someone going about 90kph when I was in a traffic jam and the officer was very pissed at the person ramming a stopped car.

Of course the challenge is that it might be high stakes without your knowledge.