Man, President Snow was ******** awesome. A truly excellent character, especially in the second and third books, where he actually got to shine. Honestly, I think he's the most effectively executed character in the series. He and Finnick were both just incredibly excellent.
I confess, Katniss got on my nerves a lot, as a character. All her wishy-washy self-loathing and flipping around with her FEELS about BOYS and stuff got on my nerves, especially when she was such a solid feminist character most of the time when people actually brought stuff up to her. But I was pleased that she had limitations, and that in particular her limitation was strategic intelligence and empathy-- it's an unusual flaw for a main character to be kind of dumb, frequently slow on the uptake, and to struggle as much as Katniss did to read others' motives and emotions. Executed well-- in her element, she was smart, and once she got the gears turning, she could plot with the best of them, but she was always so easily manipulated by people who could think circles around her-- and that was a lot of people.
All in all, I didn't really get to know any of the "mean" tributes well enough to actually dislike them. They kinda showed up, tried to kill somebody, and died.
In the end, the one I really didn't like was Gale. He joined the rebellion and forgot who he was, and participated in the worst kind of hedonistic calculus-- the kind that assigns no value to the lives of anyone he can convince himself is an enemy.