My huge pet peeve - I tell my wife that people blank out and try to 'choose their own adventure' rather than sticking to a single lane through the intersection.
It's so wildly dangerous to change lanes in an intersection, but people find it easier to adopt a 'fuck you' mentality while driving. There was a similar post to his on reddit a few years ago, and when this was pointed out it rapidly devolved into name calling.
Damn shame driving is so integral to the layout of the US.