Anyone who has been a cop, or worked in an emergency room, or customer service etc., knows this face. Perhaps I should change that to "Head." Pighead, hothead, sorehead and of course knucklehead all apply.
This is the head/face/expression of the troublemaking, unreachably resentment fueled antagonist to all reason. There are conservative versions of this head but I think that the left has more as they traffic so heavily in resentment. Whichever party, we recognize him as the ticking time bomb we wish we could stop, but can't.
You know when you encounter Mr. Head. He's the man who grows angrier as the beer flows. He's the political ranter who believes that governments exist, not to apportion spoils, but to see that he never gets any. He is the guy who is always looking for an excuse. He's the guy with a wife who cringes. He is the man against whom an ancient insult has been enacted. He will spend his life trying to get even for it.
Fortunately, he is also the kind of man is so shaking with rage that he can't shoot straight.