" The two techniques I refer to are undoing what has been done and isolating. The first of these has a wide range of application and goes back very far. It is, as it were, negative magic, and endeavours, by means of motor symbolism, to ‘blow away’ not merely the consequences of some event (or experience or impression) but the event itself. I choose the term ‘blow away’ advisedly, so as to remind the reader of the part played by this technique not only in neuroses but in magical acts, popular customs and religious ceremonies as well. [...] The same purpose may perhaps account for the obsession for repeating which is so frequently met with in this neurosis and the carrying out of which serves a number of contradictory intentions at once. When anything has not happened in the desired way it is undone by being repeated in a different way; and thereupon all the motives that exist for lingering over such repetitions come into play as well. [...] The second of these techniques which we are setting out to describe for the first time, that of isolation, is peculiar to obsessional neurosis. It, too, takes place in the motor sphere. When something unpleasant has happened to the subject or when he himself has done something which has a significance for his neurosis, he interpolates an interval during which nothing further must happen—during which he must perceive nothing and do nothing. "

― Sigmund Freud , Inhibitions, Symptoms and Anxiety