Denial is probably one of the best-known defense mechanisms, used often to describe situations in which people seem unable to face reality or admit an obvious truth (i.e. "He's in denial."). Denial is an outright refusal to admit or recognize that something has occurred or is currently occurring.
Dissociation is commonly displayed on a continuum. In mild cases, dissociation can be regarded as a coping mechanism or defense mechanisms in seeking to master, minimize or tolerate stress – including boredom or conflict. At the nonpathological end of the continuum, dissociation describes common events such as daydreaming.
Projection of marital guilt: Thoughts of infidelity to a partner may be unconsciously projected in self-defence on to the partner in question, so that the guilt attached to the thoughts can be repudiated or turned to blame instead, in a process linked to denial.
Regression (German: Regression), according to psychoanalyst Sigmund Freud, is a defense mechanism leading to the temporary or long-term reversion of the ego to an earlier stage of development rather than handling unacceptable impulses in a more adaptive way.