How can you tell a good person from a bad one?

I don't really think there's such a line between a good person and a bad, some people will have more violent or judgmental tendencies but I believe there will always be good in a person. It's important to remember that, that person wasn't born necessarily born like that. Their surroundings and upbringing helped to shape and mold who they became in accordance to their own personality traits and although that doesn't justify their actions, it provides a view that they can't really help who they are. It's not whether someone is good or bad, it's whether you feel you can look past their flaws, because ultimately whether it sounds selfish or not; you're looking out for you and if a person is more harm to you than they are good then they shouldn't be in your life.