Although descriptive psychopathology of obsessive-compulsive disorder (OCD) is well-established, this disorder still presents very enigmatic and puzzling aspects. Hence the usefulness for further contributions to better clarify the picture. For example, one of the most problematic manifestations of OCD consists in pathological doubt, whose origin, however, remains unclear. For this purpose, a psychopathological analysis of several cases of OCD, in which decisional uncertainty is involved, is conducted, as well as a rereading of a famous case by Freud. As a result, the existence of a new psychological phenomenon observable in OCD people is suggested. It is proposed to call it: "incompatibility perceived between unbiased commitment and satisfaction for an unexpected and effortless personal benefit" (ICB). In fact, when an OCD subject experiences a sense of commitment, be it interpersonal or impersonal, he/she will experience the satisfaction for an unexpected and effortless benefit that results from the commitment, as incompatible with the commitment itself. As result, the subject will consider the satisfaction for the benefit as true but inacceptable, whereas he/she will consider the sense of commitment as desirable but as false. This phenomenon not only seems to explain at least some cases of indecision typical of OCD, but sheds new light on some important explanatory concepts, such as 'ambivalence', 'self-ambivalence' and 'fear of oneself', called into question over time precisely to explain the varied psychopathology of OCD. Finally, it also seems to have important implications for psychotherapy.