There are no limits on true self-giving. It is not just to those one likes that one makes the offering. This involves a love that issues from the very CENTER of the person's being, directed to the CENTER of the other person's being, a love that gives ALL that the person is in order to foster the other person's life, a love that is offered to EVERYONE, without exception and without condition. The love is not offered to people because they are one's friends; people become "friends" because one loves them.
Most people mistakenly believe that all you have to do to stop working is not work. The inventors of the Sabbath understood that it was a much more complicated undertaking. You cannot downshift casually and easily. This is why the Puritan and Jewish Sabbaths were so exactingly intentional. The rules did not exist to torture the faithful. They were meant to communicate the insight that interrupting the ceaseless round of striving requires a surprisingly strenuous act of will, one that has to be bolstered by habit as well as by social sanction.