When is a good time to get hurt?
The only good time is to get hurt a little before we get hurt a lot, like how bracing yourself from falling can sting, but it hurts a lot worse when you don't. When you are preventing a bigger pain, it is ok, but there are still ways to make the hurt less painful. Just use your own feelings to be sensitive of theirs.
So if that's the only time when it's ok to hurt, why do we do we hurt people all those other times?
It's because we are insecure about something and don't know how to react to certain people. Some people react more viciously to more people than others because everyone also handles their problems differently. For example, children in the same environment, like siblings, usually turn out completely different. Just like people that have faced the same pains have different ways of turning out because of it.