When I am driving my car, I find it irritating when other car drivers do not just take their right of way, shooing me through as if they are being polite. All it does is slow everyone down and increase accidents.
Same with bikes. Just faster and safer to be predictable.
Also, I am the only cyclist in my family, and I live in a community that has a fair number of anti-cycling drivers. I always groan when I'm driving with family and friends and some cyclist doesn't just act like a car. Those are the cyclists my non-cycling friends use as examples of why bikes shouldn't be on the roads at all.
I consider riding like a car to be good for cycling PR.
"The best rides are the ones where you bite off much more than you can chew, and live through it." ~ Doug Bradbury