This right here. I mean, I understand if a character isn't a nice person at first, like their personality has work to do. For example, if a character has trouble connecting with others and is a bit of a butt, but not to the point of verbal or physical abuse of other characters, including their love interest. I like the cold to warm change of a person if, like you said, they realize how their attitude or behaviors aren't okay. There are characters that are the way they are because of their pasts or their upbringing, which doesn't excuse them but it's something to understand about the character. If they realize change will better their own life and they can become a better person, that's a step in the right direction, but personally I don't like the possessive/abusive. Cold to warm person change, sure, but when a relationship is looking to be toxic/unhealthy I will drop that series and I hardly drop anything because if I get too deep into it, I have to see the end. Even terrible movies xD But nope, possessive, abusive, toxic, or unhealthy are no-go for me.
@cherrystark: Like right? xD I can hardly "control" my own life, I can't imagine what kind of people have time to control other people's life, that's just crazy in my opinion!