I think it comes down to a balance between your need to get where you are going without excessive stopping, and facilitating faster cars to get around where you can. Many roads do have stretches with longer lines of sight where a car or two can pass you. Try to encourage that by slowing down a little (or at least not speed up) and staying to the right in lane and hope a car or two gets by. . That would be one less need to pull over. In dense fast traffic let the full five cars build up, then look for safe convenient turn out. Don't let them bug you or get on your nerves back there.
As far as contrasts with other areas, I see it as a traffic density thing. In rural Utah, the density is so low that nearly everyone has a chance to pass before building up too many cars behind. In many areas of CA (and other states) there is more cars, in both directions, which limit passing ability. Because today's cars handle so well, they're taking corners at higher G forces than ever before. So we accumulate a string of cars very quickly on heavily traveled two lane.
