For example it's standard in LA that when the light turns yellow then two cars are able to make a left turn in time to not back up the perpendicular Lane.
Or if you are turning left you should try to make room on your right, so that those going straight can get around you. No way Waymo vehicles will be doing that.
All in all there are certain behaviors that are necessary in a city with traffic like LA that would certainly be outside the strict safety parameters that (I assume) Waymo operates under.