When i look at it now, the north as a whole is one of the most exceptional areas in Westeros. The've been craving independence since season 1 and while I can give a pass to the first time, since they were at full power, their warden killed and his daughter is taken hostage, and the fact that every-time a Stark travels south bad shit happens, them pulling the same shit at the end of season 6 is just dumb. They think the "king of the north" shit will work again despite the fact that at this point in the story, one house is completely extinguished, their forces were diminished by the war of the five kings and the northern civil war, winter is coming, darth maul is going to invade, and that their strongest forces aren't even from the north. Then, when their king brings Daenerys in to help with the zombie infestation, these idiots are more worried about Jon not being king than the giant gaping hole in the wall and thousands of undead shuffling in (one of the houses even straight up leaves). And after a battle that killed off like three more northern houses and another half of their forces gone, they go into another battle that killed off a small portion of their forces. In the end, they somehow get their independence in the end, despite the fact that they probably have only about 2-3 thousand men at best, their food supplies are most likely diminished from the war, and that the current king of the seven kingdoms is a Stark. So by the end of the series, four houses are extinct (to be fair, the boltons had it coming), there's four empty castles, military is too weak to defend against invaders (the seven kingdoms at least still has dorne and part of the reach to rely on), and the north seceding means the seven (six) kingdoms aren't entitled to giving any aid (though the north might get aid because of Sansa's connections with Bran, at least 3-4 regions are also in dire need of assistance, having been ravaged by war as well)
TL;DR the north is full of idiots only rivaled by the ironborn