Discussion: How Much Variance From The Norm Do You Put In Your Worlds?

When looking at cultures, real and fictitious, there is the tendency to assume that people fall into the stereotypes of the norms and values. A member of the Samurai caste from 14th century Japan is assumed to act a certain way....which then leads to the belief that all Samurai caste members from 14th century Japan acted that way. This is problematic. Not only is there the fact that the 14th century is 100 years (and look at how much our culture has changed in just the last 10) and that Japan is a big place, but also people just don't act that way.

Still, it persists in historical discussions, and in RPGs. To flip the lens around, people arguing about our culture would get into arguments because someone suggested that Americans on the highway partook in casual speeding. When, obviously, that couldn't be the case because the US was a country of laws, with Rule of Law, and the law said to not speed. Right?

With that said, do you worry or bring this concept into your own game? Is there the expected norm (don't speed) and then the actual norm (lots of people speed all the time, and as long as it's not too egregious no one cares?)

If not why not? If so, do you find it adds to your game?