Why is it necessary for the normal life of society that all people not only have rights but also fulfill obligations?

For a normal life, it is necessary that people not only know their rights, but also fulfill their duties, because if some people do not fulfill their duties, then it may become more difficult for other people to live. For example, if the father does not pay alimony, which is his duty, then the mother and children will not be able to live normally, also if people do not pay taxes, etc.