There is no one way by which you can explain and interpret human behaviour. Infact its impossible to claim to have understood and known someone completely. Just when you think you know someone, an all together new facet is revealed to you.
When you label someone as bad, think if thats really so? Or is it just your perception? Are they beyond your reach, or its just the circumstances? And to make matters worse, you are responsible for those circumstances?
When you like someone, you just do so without any reasoning. Despite the various instances that they do bad to you, or atleast thats what it seems on the face of it. You will forgive them for thousand sins and many more. And when you hate someone, you dont need a reason to do so. You just hate them for no rhyme or reason. No explanation given, no explanation required.
So, the deeds dont play much of a role in making you like or dislike someone. I guess nobody is good or bad. Its your thinking that makes them so.