Having driven quite a lot in the SFBA (SF Bay Area, right?) it's usually out of frustration with traffic clogging up the left half of the highway. Lazy careles

Having driven quite a lot in the SFBA (SF Bay Area, right?) it's usually out of frustration with traffic clogging up the left half of the highway. Lazy careless drivers leave the right lane underutilized, congregating on the left side because they can't be bothered with monitoring let alone handling potentially merging traffic. So the right lane often becomes the only way to get around these clumped up clusterfucks, and to minimize time spent in the right lane while overtaking, it often occurs at quite extralegal speeds.