People is the simple answer to live for. You need Doctors, Farmers, Businessmen, Policemen, Dreaded Politicians, and etc. if you live for these people your life will be much easier.
Family and Friends are really only necessary to your perceived happiness. If you get sick can your family and friends cure you, Do they provide your food, your money, or you security from others. Unless you live off the Grid, people are the most important. If you live off the grid including medical drugs and surgery creating everything yourself then it could be family and friends.