Rules and laws are important because the society needs something to go off of. For example if someone were to steal from the store and get away with it, every one would be doing it. If someone were to kill a person and get away with it, then society would automatically think that its okay, and the whole world would go crazy about killing people they don't like.
So its important to have laws and rules to keep people in check and to keep our society safe.
Hope this helps:)