No matter how good you are with someone, in certain situations you have to be mean, to be awful, to be who you actually might not be. People and their actions are what determine our reactions.
An action is what we do, in general are two types of actions one might do. First are those actions that affect only ourselves, like bad decisions or inappropriate behavior with no reason; and secondly are the actions that affect the others around us, treat somebody unfairly, take advantages, fool people, lie and the list goes on. In both situations, sadly, you are judged by what you did and why you did. Actions can also be positive and therefore you might influence people’s perception about yourself. You might be the most innocent for some and the devilish for others, you can be anything you do. It also due to how people interpret your actions and the situation the action was made.
Reactions are usually the actions after an action, which mean the way you act the other will react. It is true that in some situations we do not have the expected response, because some things can be also unpredictable, and people in general are the most unpredictable creatures on Earth. Many times what we see and we believe is the most logic interpretation is not actually how it is, because each one of us has its own way of perceiving thanks to our moral values, cultural behavior, religion, interests, status, family, past experiences, knowledge and so on.
Actions, reactions, does not matter, important is to treat people fairly and when we have a bad though about someone, before judging try to put yourself in his/her shoes for a second and try to understand if your action is worthy.