Which of the vanilla races do you think is most arrogant and why?

Altmer literally believe not only that every race is beneath them, but some members of their race are perfect. Those who aren't deemed perfect are cast out of Summerset and exiled.

nords, by far, their arrogance kickstarted the rise of an empire

Altmer. I don't really see the Nords as arrogant. Sure, they are, but they're mostly suicidally prideful.

Altmer.

Sure, every other race is arrogant in their own way, but the Altmer take the cake. The Thalmor, while not fitting the beleifs of all Altmer, are actually the extreme end result of Altmer pride and haughtiness.

This isn't a new characterisation: There's mention in Morrowind about how self-absorbed the Altmer are, IIRC.

Might as well say they're born arrogant.

Altmer. Nord a close second. Of course, nords aren't almost universally asses, so that helps a lot.

Nords have always been arrogant ever since I've been playing with imperials a close second