People around here like to play a game where they'll tailgate, pull over one lane to the left, then pull in front of me before slowing down. There's no rhyme or reason to it. The unofficial "rule" around here is to go 5 mph above the posted speed limit, which I do. No amount of signalling, staying in the appropriate lane, or otherwise driving intelligently fixes it. I've even had a cop do it to me.
Close to my actual neighborhood, sitting at green lights and waiting until the last possible second to turn out onto the main road are common too. You develop a spidey sense for those after awh