To spoil means to put no limit on caprice, to give one the impression that everything is permitted to him and that he has no obligations. The young child exposed to this regime has no experience of its own limits. By reason of the removal of all external restraint, all clashing with other things, he comes actually to believe that he is the only one that exists, and gets used to not considering others, especially not considering them as superior to himself. This feeling of another's superiority could only be instilled into him by someone who, being stronger than he is, should force him to give up some desire, to restrict himself, to restrain himself. He would then have learned this fundamental discipline: "Here I end and here begins another more powerful than I am. In the world, apparently, there are two people: I myself and another superior to me.
Ortega y Gasset
psychology