Vex - Sure she can be a bit sassy, but I don't think it's too bad. She does get sarcastic with Delvin too which I find humorous.
Sapphire - I don't hate her and she does warm up to you after a time, but she never does tell you where she got her name from/ true name
Cicero - Yes. Very irritating ans whiny voice. Interesting clothes though
Aela - All the Companions talk down to you until you make your way up their ranks. I think it's just intended that way. The whole lot warm up to you as you make your way up the ranks.
Ulfric - It's intended that way, I think. Intended to make him look like he's only rebelling to get the throne for himself. The conceited attitude of the leaders in each side of the civil war is what stops my characters from helping either side. I wish your character could be just like Talos in that respect too and try to unite everyone yourself.
Astrid - My only problem with her was that she got too paranoid in the DB questline, but of course it was part of their story. Otherwise, sixiest voice in the game IMO. The DB quests themselves is what got me to start annihilating that guild.
Karliah - This one is the opposite. A lot of people actually hate her because she shoots you instead of the other guy. I actually liked her.
Rolff Stone-Fist - I dislike this guy with a vengeance after the treatment my Argonian character got from him. Challenged him to a brawl and some mod glitch/ bug caused him to pull a dagger each time, where he reneged on his bet. Top it all off with him being essential for what reason I do not know.
Ahtar - First two times meeting this guy he came across as arrogant. Saying he's just doing his duty, also complains about Jaree-Ra and does nothing about him.