He doesn't seem to give two craps about Nordic culture and is a bit insensitive about about their values. He is a general sent to do a job because he was a skilled tactician and strategist, not for his super sparkly personality. For the most part I don't 'hate' him, he strikes me more with a strong degree of annoyance.
Rikke: "Balgruuf refuses the Legion's right to garrison troops in his city. On the other hand, he also refuses to acknowledge Ulfric's claim."
Tullius: "Well, if he wants to stand outside the protection of the Empire, fine. Let Ulfric pillage his city."
Rikke: "General."
Tullius: "You people and your damn Jarls."
Rikke: "Sir? You can't force a Nord to accept help he hasn't asked for."
Tullius: "If Ulfric's making a move for Whiterun, then we need to be there to stop him. Draft another letter with the usual platitudes, but this time share some of your intelligence regarding Ulfric's plans. Embellish if you have to. We'll let it seem like it's his idea."
Rikke: "Yes, sir."
Tullius: "You Nords and your bloody sense of honor."
I don't think it's that he doesn't care. I think he is much more pissed off and annoyed than anything - I'm pretty sure that I'd be pissed off if I was in his shoes too though, and completely understand why he would be angry.
Now as for who I hate.
Ulfric, definitely near the top of the list. The Thalmor agent in Markarth, and Ancano. Astrid, I didn't like her very much either.
I like Cicero, lol. If I had to play caretaker to a corpse my entire life, Constantly speaking to it, and wishing it would speak back. Well I'd be mad too.