" The ego now proceeds to behave as though it recognized that the symptom had come to stay and that the only thing to do was to accept the situation in good part and draw as much advantage from it as possible. It makes an adaptation to the symptom—to this piece of the internal world which is alien to it—just as it normally does to the real external world. It can always find plenty of opportunities for doing so. The presence of a symptom may entail a certain impairment of capacity, and this can be exploited to appease some demand on the part of the super-ego or to refuse some claim from the external world. In this way the symptom gradually comes to be the representative of important interests; it is found to be useful in asserting the position of the self and becomes more and more closely merged with the ego and more and more indispensable to it. "

― Sigmund Freud , Inhibitions, Symptoms and Anxiety