The anal character trait is also well suited for displaying feelings of hate… flatus keeps people at a certain distance… it means a defiant emphasis on self-contempt… The tendency toward displacement onto anality may be enhanced by the presence of an abnormal store of retained trauma.
Ferenczi argues that anal character traits serve as vehicles for displaced hatred and self-contempt, and that regression to anality is intensified by unresolved traumatic retention.
, The Clinical Diary of Sándor Ferenczi, 1932thesis