There are much better examples of subjective cultural norms than greggman provided. The notion of personal space, for example, varies significantly between cultures, and there is no significant objective reasons one norm is better than other.
Even among one culture (whatever it means) there are countless of better examples of things that cannot be sorted out in the jerk / non jerk category.
Usually people that work at night, how much noise they can make when they came back home early in the morning? What about people practicing music instruments? Can students party at night if they have neighbors, just once in a year? once in a month? Is it ok to bring a stroller in crowded areas? etc.
I don't think it's possible to give an answer to any of these questions that will get more than 60% agreement in any sufficiently diverse community, even given the full details of the situation.
In the general sense the the USA as a whole tends to value individual freedoms over the collective. It is a individualistic culture. Sometimes I wish that we were a more collective culture. Not much more, but I think there are pros to being more collective than we are because as humans we are social animals.
I don't know if it is just me but I think perhaps we have gotten more individualistic in the past few decades and those questions would illicit different responses 40 years ago. Hitchhiking used to be common but now we are afraid strangers are going to kill us, even though the world is actually safer today. I even admit I am absolutely terrified of random stranger violence, irrationally. I know that if I were to become a victim of violence it would be far more likely to be someone I know who did it and not a random stranger on the street. Most people are not killers or serial rapists or muggers. Yet, I still can't shake the fear.
But you are right, those answers would very much vary between countries.
Those are my thoughts on the matter anyways, for what it is worth. (Probably not much :))