Certain negative tendencies of his character, by now controlled and largely suppressed but still lying latent in the subconscious, may rush up to the surface at intervals if impulsiveness is present. When he is taken off his guard, they appear in speech or even action until he recovers himself. The damage is done and although he returns to normal freedom from these faults, the consequences may remain and make him suffer for a disproportionate period. The farther he advances, the more important is the lapse.
-- Notebooks Category 11: The Negatives > Chapter 2: Their Roots in Ego > # 51