2: Repression
Repression can be considered an act of forgetting, done unconsciously. A person represses various unacceptable memories, desires, ideas, or emotions that are incongruous with the deception they are attempting to uphold.
Suppression is similar to repression, but the critical difference is that the "forgetting" is a conscious rather than unconscious act. People regularly suppress negative thoughts and emotions to manage their emotional state: a person who is afraid of public speaking is well aware of his fear but intentionally chooses to ignore it or distract himself from it, or a person may be angry with their friend but choose not to let it show. This is not the same as self-denial, as the individual is not denying anything - and the author refers to it as a "much more mature" operation that repression and is usually undertaken to produce a positive outcome.
The difference between repression and denial is that denial is external: People deny what they perceive, but represses things that are internal to themselves. The two of them are efficient coworkers: if an external stimulus cannot be denied, our thoughts and feelings about it can be repressed.
Freud considered repression to be a building block for other ego defenses, which require certain facts to be omitted or substituted. Consider an abused child who wishes to distort his memories - not only must he emphasize or invent positive experiences of an abusive parent, but he must repress negative experiences. In this way, repression is necessary to distortion of memory.
That which is repressed is simply ignored, but it still exists. It can (and often does) resurface in "strange and disturbing" forms. A person may be irritable or anxious, have nightmares or insomnia, suffer depression, and develop phobias or tics - and claim to be unaware of the reason for these conditions. In particular, repression often expresses itself in the form of fear or anger toward something that reminds a person of something he is attempting to ignore.
Freud's "Studies on Hysteria" (1895) formulated the theory that neuroses originate in the repression of traumatic experience, and the psychoanalytic method of treatment focuses on uncovering memories so that the patient may experience a catharsis and then process these memories in a conscious manner.
However, it is admitted that the psychoanalytic approach is prone to confabulation and the invention of false memories, which are more comfortable for the patient to use as a scapegoat while continuing to repress the real cause of their condition.