Randomly speeding up or slowing down, and changing lanes without signalling is called "Massachusetts Mode".
It's just in the Boston area where that happens. Once you get to Western Mass, driving becomes more or less normative.
Still, I've done my share of Boston driving. The most annoying maneuver I've encountered is when you are making a left hand turn and the car behind you cuts you off making the turn before you thereby gaining the positional advantage.
I would cast further aspersions upon Boston drivers but one time I was hopelessly lost in the heart of Boston and realized I was driving the wrong way down a one way street. So, sometimes I'm the douchebag, I guess.