Once again, to start the discussion on Yuu, I’d just like to say. He is, indeed, quite rude. However, his rudeness doesn’t show on the outset. He actually acts like a decent member of society on the outside, and keeps his snide remarks in his own head.
We see this in the first chapter of the 4-koma: Yuu starts acting all cool to get attention of some of the girls but doesn’t realize that his plans are being subverted by Nao, heh. Of course, his intent in this is purely for self-satisfaction, and gives off his narcissistic vibe.
Even in the special broadcast, released yesterday, it shows once again, with a preview of the first episode. (Episode 1 PV spoiler) A seemingly meek girl confesses to him, and he makes an excuse about studying as a means to reject her. However, when we hear his inner thoughts, we find out that he’s really just toying with her. Of course, my Japanese isn’t good enough to understand the whole dialogue, so I might be getting some things wrong with this 
tl;dr he is very egocentric, and uses it to his own advantage. This screams a whole lot of character development in store for our protagonist, if anything 
