One vague question: How can people live with themselves after hurting someone? :(

Now im guessing you are specifically referring to someone who is intentionally hurting someone and knows the consequences of what they do to that i'd say this; people are different for one. Some people lack empathy or sympathy, or perhaps one might feel justified for hurting someone because they were hurt first, but besides that sometimes you hurt people without intending to and kids intentionally hurt people all the time because they dont know better.