I liked everyone.
One thing that will generally result in me LOVING the heck out of a work is if instead of just good vs evil or whatever, antagonism is caused due to flawed individuals who just happen to desire different things to the point of conflict of interest.
Anna didn't mean to trigger Elsa. She just wants a normal (inasmuch as royals lead "normal lives") life, and her memories of anything that would have actually been conducive to fixing things were wiped.
Elsa didn't mean to create the eternal winter. (She also didn't mean to do anything bad, really; you just cringe at that party where she's trying so hard to reconnect with Anna but somehow everything she says just manages to hurt her sister even more). She means well, and acted in a way that she thought was the best way to control her powers, but actions have unintended consequences, especially when you misinterpret things.
Hans, all in all, probably wouldn't have been a bad king (which is entirely different from whether he was a good person, mind). This guy's in the butt end of the line of succession. Now he suddenly has an avenue into a throne, and he only needs to bump off two people instead of twelve to do it, and better yet one of them provided an easy avenue by which to bump off the other. Also, he did give the castle's supplies to the smallfolk/peasants when everyone was freezing. Now, that could have been merely meant to curry favor with the local population, yes, but I am an economist and as such believe that 1. there's no reason why doing a good act and being rewarded by feeling good is inherently superior than being rewarded by something more material and 2. it does not matter the motivation, only that it is good. Besides, real life royals in history have done far worse things for power than what Hans did, and plenty of those have turned out to been not bad rulers. When you play the Game of Thrones, you win or you die.
Also just want to add that I expected to hate Olaf and was pleasantly surprised when they used the fact that as a living snowman, he's nigh-invulnerable, and then play it for black comedy up to eleven