Enjoying life?

It could also be that they don't realize that they have hurt someone. Or sometimes the hurt is unavoidable, like when you break up with someone. Some people also understand that people don't typically dwell on the bad things others do to them. Forgiveness is a real thing and you can grow as a person simply by moving on and not doing to others what has been done to you.

Hmm. It's either they really hated the person, or they don't even care about that person, or worse, they do not have any conscience at all. it's sad, isn't it?

Good question. I think part of the answer might be they don't care. Sometimes they justify hurting another because they feel hurt themselves, at times even for past unresolved issues. It's sad because life is really too short to hurt or even feel hurt for very long.

Maybe due to lack of concern for others or the lack of emotion in doing things. Insensitivity can be the reason because they are too focus on their goal of enjoying life that they tend to get it at all costs even through the process hurting other people. A lot of criminals nowadays don't even know the concept of having a conscience. It really is a harsh truth coming at us right now. Don't worry, what they do unto others will be done to them too.